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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

Sister ruined Christmas with stupid affair drama - AIBU to be really stressed?

243 replies

aerisgainsborough · 09/01/2026 13:32

It’s a long one, grab a brew and a biscuit.

I’m 36, sister B is 33, sister C is 31. All married, I have 3 children, we’re close knit, live within 5 miles of each other and do stuff with each other and our parents all the time. Middle sis has always had issues with self-esteem and either hates herself or loves herself. Has always been impulsive and attention-seeking (my youngest sis and I think she may have BPD).

B’s husband is a bit of a wet lettuce and very surface-level, is a bit ignorant and only speaks to my kids to tell them off in a really patronising voice.B He has “not made his mind up” on whether or not to start a family so B is kind of stuck in limbo on that and they won’t discuss it. She tries to let on that she doesn’t want children, but it directly contradicts what’s she’s said before and she flip flops constantly. They have very few commitments, a cat and a weekly board game club, and sit playing online games all weekend and that’s about it but reckon they live busy lives.

However, B cheated on him 10-ish years ago and he forgave her, which made us all lose respect for both B and for him because she really was horrible to him. He then proposed and they’ve been married for 5 years. He struggles a lot with anxiety etc and she says she feels more like his carer, but we’ve never seen any behaviour to support this so just generally have to take her word for it.

Recently B started a new job (she changes jobs nearly every year) and has got friendly with a male co-worker who is 10 years younger and they’ve started up a fling, despite them both being married. She “left” her husband almost immediately and declared her love for him. He strung her along for weeks, saying he couldn’t leave his girlfriend yet, going through phases of constant messaging and then ghosting her. Eventually she confronted this lad and said she loves him and he’s told her he regrets it all and nothing can happen. I was sworn to secrecy during all of this and nobody else knew but me, which was horrible and during Christmas week so I spent the whole Christmas period hosting the rest of the family while B and her husband went and played happy families with his side. I’m autistic and had a very intense internal struggle with all this. I was crying, feeling sick, unable to think about anything else. I was trying to cope with everything changing, her betrayal and not being the person I thought she was, them already being split up but not telling anyone, When it finally all came out and she told everyone, they were all angry at her for putting me in that position. It’s all everyone has been able to talk about since and my mum keeps trying to get me to find things out. I’m the eldest default child who gets leaned on by everyone and I’m just so tired.

So B is now just living with her husband as housemates and helping each other set up dating profiles. She is meeting up with a 40-odd year old she met on a kink app and during a phone call he told her that he had massive hands and could choke the life out of her if he wanted to. I’m sitting there listening as she tells me she’s meeting up with him at his flat in Manchester and I am now picturing her being chopped up and dumped in a bin. I’m trying to put some distance between me and her problems because we all get a bit enmeshed at times and it’s not good for my mental health but I am worried sick that something will happen to her.

My parents fully believe that B and husband will get back together and don’t know about B being “on the apps”. I’m sick of them asking about it and just don’t know what to do about it all. Thank you, if you’ve read this far.

OP posts:
WallaceinAnderland · 09/01/2026 15:11

Yet another poster who wants someone else to change their behaviour but is not willing to change their own behaviour.

This is totally within your control OP and you are choosing to engage.

You say that if you don't there is drama. So what? There's drama anyway.

Use the skills you have been taught and your professional knowledge to put healthy boundaries in place. Stop blaming your sister for your own behaviour.

beAsensible1 · 09/01/2026 15:15

why were your parents so angry at B for putting under all that stress if they’re keeping it up by asking you. Villainising her for leaning on you and then doing the same.

I assume B is confiding in you in sisterly way as you say you are close. If you do not wish to be confided in by her then you should say. If she keeps going hang up the phone.

BPD is quite a big thing to have and manage has you all spoken to her about it properly? Or were you being flippant?

it sounds like her marriage is all over the e place but they’re at least talking to each other about and not lying. So that’s better than nothing, can you ask your other sister to keep and eye if you are worried and take a step back from everyone for a bit.

sausagedog2000 · 09/01/2026 15:15

YANBU about being worried about your sister meeting up with the big band psycho. I’d do anything I could to talk her out of that. If it was my sister I’d actually physically stop her leaving the house that night.

Clarehandaust · 09/01/2026 15:17

I think you do want to know what’s going on in your sister’s life when she’s chatting to somebody who has told her that he could choke her to death
I can’t believe some of you a lot would step back frankly that’s just awful behaviour

MrsCompayson · 09/01/2026 15:17

I don't understand most of these responses to be honest. You don't ask for this drama in your life, your sister is trying to drag you into her drama to validate her awful behaviour.

1.You have to put in firm boundaries. If they ignore them, you have to go no contact at least for a while.

  1. Only you know the dynamics of your family, but is seems as though your parents are quite happy for you to do the parenting, so they can avoid the backlash. I wonder how it was for you all growing up? Was your sister a handful? Did mum and Dad always let her have her own way? Just a thought, try to explore the dynamics, see if you can make sense of it?

I probably have no right to say this as I don't have any first hand experience of ND myself but I just wanted to say that you don't need to worry about getting things wrong/judging the situation badly, just that you are feeling a certain way and recognising that. What I am trying to say is it doesn't make your opinion crazy, irrelevant and less valuable. Hope I haven't offended by saying that.

Bloozie · 09/01/2026 15:17

Ah bless you... You need to be really clear with your sister and your parents that you don't have the bandwidth to deal with this right now, and they both need to dial it back.

It's easier with your parents because you can simply say, 'My autistic brain cannot cope with having to dive into this every time we speak. I don't agree with what B has done or is doing, but it's her life to lead and we have to trust her to get on with it. I'm not inserting myself into any of the drama, and I'd really like it if we can talk about something else as us constantly talking about whether she'll get back with her husband won't change the outcome, I don't know any more than you do and it's frying my brain."

A more delicate approach with your sister is probably needed, as she feels she needs your support and you have no energy left to give. Maybe something like, "B, I love you but this is all so far outside of my sphere of experience that I'm just not the right person to advise you on dating etiquette, or kink, or any of it. And you know I felt really uncomfortable lying at Christmas. If I'm completely honest, it's all starting to make me feel quite anxious - which is perhaps a me problem, a feature of my autism, but either way, I love you and I support you but I can't deal with being so immersed in your love life right now. I don't know what to do with much of the information you're giving me, I don't know how to play the apps and the dating game - and that feeling of genuinely not knowing but wanting to support you is stressful for me. I think (C/her best friend) might be better placed - or have you thought about joining a community like Mumsnet?"

MrsDoubtingMyself · 09/01/2026 15:19

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WilfredsPies · 09/01/2026 15:22

‘Heavy is the crown of the eldest daughter’. Have you read that poem? I think you might find it hits home a bit.

I cannot imagine being anything other than frantic with worry if one of my younger sisters told me they were off to the flat of an internet stranger who was looking forward to choking her. Especially if she had a history of unwise decisions. You’re damned if you do say anything and damned if you don’t, especially if she finds herself in a situation she can’t get out of. It’s too much pressure, even without being neurodiverse.

I think that the next time she starts to tell you something, you have to interrupt her and tell her to stop. Tell her that you’re not her therapist and you’re not keeping any secrets for her, especially when she’s doing really stupid stuff. Tell her that you love her but you just can’t do it anymore because it’s making you ill. And then speak to your parents. Tell them she’s on dating sites, she’s talking about going off to meet complete strangers and that they need to talk to her because you cannot deal with this anymore. She is their daughter, not yours, and you can’t sleep at night for worrying about being responsible for everyone, from her safety and keeping her secrets, to them being kept updated with what’s going on. It’s too much and you’ve hit your limit. If anyone starts to argue or justify or says anything other than ‘ ok, that’s fair’ then end the conversation immediately. Don’t even let them finish their conversation. Either hang up the phone or walk out the door. They need to see that you’re serious.

InMyOodie · 09/01/2026 15:22

You really don't like your sister B. She must know that. I feel sorry for her. You are so sneering about her and how she 'hasn't matured beyond her 20s'. Maybe be less smug and give her some space.

Givemeausernamepls · 09/01/2026 15:24

your sister sounds really unhappy and it sounds like you, your sister and mum are constantly talking about her and judging her.

if you don’t want to be involved that’s fair enough but that extends to not gossiping etc. just grey rock with oh that sounds really hard, or I’m sure you’ll be able to figure it out.

silverwrath · 09/01/2026 15:30

With respect, your sister is a 33yr old nightmare. God knows what her actual problems are. Either she just thrives on chaos. Or she has something 'diagnosable'.

But. She is not your responsibility.

She's a grown woman. Who has a mother, ? a father and 2 other siblings. Why are you shouldering the burden of her poor decision making and the consequences of same?

You've been given very good advice from a couple of commenters on how to step back and disengage from her drama. Please take it.

Concentrate on yourself and your wee family unit. Because I highly doubt you can change your sister's behaviour. But you can change yours.

Best of luck. 🌸

GasperyJacquesRoberts · 09/01/2026 15:35

aerisgainsborough · 09/01/2026 14:17

I lost respect for him not having some pride in himself and running in the opposite direction. He begged her to take him back even though she was in the wrong, she played mind games with him and it was very sad to watch.

Sadly abuse victims often go back to their abusers.

SmileyMoonset · 09/01/2026 15:39

I’d be pretty cross with my sister however this is not your circus or your monkeys. She’s an adult and entirely responsible for her own behaviour and actions.

Drop the rope:

I love you but I don’t want to discuss your marriage or your dating or your sex life. If you don’t stop I will have to leave/hang up/ask you to leave.

I love you Mum but I don’t want to discuss sister’s marriage or life at all. If you have questions ask her.

You absolutely have the power to reduce your own stress here.

RawBloomers · 09/01/2026 15:40

aerisgainsborough · 09/01/2026 15:00

Having boundaries and contracting with a stranger is an essential skill but maybe easier when you don’t know the person and you’re going into the relationship with those boundaries already in place. Appreciate what you’re saying though. I’m a bit of a doormat :(

I get that it feels different with family and close friends. I'm just saying - apply those skills. They're important for you even outside of work.

TwoTuesday · 09/01/2026 15:41

She ruined Christmas did she? I bet her Christmas was worse!
There is no need to for you to "take on" the stress of her personal life. If you really don't want to hear it, say so, but it seems you're getting far too invested - say no to your parents when they ask you to dish the dirt/ parent your sister on their behalf.
There was no need to sit through facetime with her and her husband either. Her husband is not your concern, he knows what she is like by now.
It's not all about you.
You seem to like feeling superior though, so maybe the stress of hearing all about her disasters has a payoff, if it does, you can't really start complaining about it now.

FerriswheelsKissesandLilacs · 09/01/2026 15:41

I recognise these patterns from my SIL who I think may have BPD or vulnerable NPD, or maybe both. But that's being unkind to people with PDs because everyone I know with diagnoses behaves better than her.

She creates chaotic drama in her own life, then pulls me into the drama and begs for me to help her. During the peak of the chaos, this will be extremely intense- multiple phone calls all day sometimes going on for an hour or more where she'll talk in circles. Usually there will be lots of crying and self-flagellation, saying she's so stupid and has made a massive mistake, and if I don't immediately contradict her she'll accuse me of agreeing that she's stupid.

This is the point where she'll threaten to hurt herself and have herself admitted to hospital, send vague messages implying intent to unalive herself or that she's in a dangerous situation, and then switch her phone off and go out of contact for several hours. She's always absolutely fine.

Bear in mind that only half of what she's said is true and she's contradicted herself multiple times so I no longer have a clear picture of what is going on. If I suggest that she's not being truthful, she'll get very angry and send barrages of abuse.

Then I'll try to pull away from the situation a bit and usually that will result in a full on eruption and might mean nasty messages being sent to my friends and relatives, rumours being spread about me etc. For other people, such as ex-partners, this is the stage where she'll call the police and social services and make false allegations.

Then we go no contact for maybe a year or two and she spins stories to all the family- who don't have the full picture about what she does- that we've abandoned her, and usually, one way or another, we end up being guilted into re-introducing contact. No good can come of it.

She doesn't care about anyone. She will only prioritise herself. Look now at how she's treated her husband and yet only cares about ensnaring the next man. The oversharing about sexual details you didn't want to know is also exactly what my SIL does. It's all about what serves her needs.

MaggieBsBoat · 09/01/2026 15:43

She’s allowed to walk home on her own and go to lads‘ houses!

You are too involved and it all sounds very judgmental and unpleasant (from you!)

BellesAndGraces · 09/01/2026 15:45

aerisgainsborough · 09/01/2026 14:58

Totally get what you’re saying though. She needs to maybe see the consequences of her actions and stop trying to filter it through me or others.

Kindly, you can’t see the consequences of your own actions and you’re older than her! You are refusing to accept the role that you are playing in this by allowing yourself to be so overly involved in her life. You have a choice and can step back if you choose to.

If it helps, practice phrases you can use to stop yourself getting drawn in.

Andflake · 09/01/2026 15:46

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EarthSight · 09/01/2026 15:46

She is meeting up with a 40-odd year old she met on a kink app and during a phone call he told her that he had massive hands and could choke the life out of her if he wanted to. I’m sitting there listening as she tells me she’s meeting up with him at his flat in Manchester and I am now picturing her being chopped up and dumped in a bin

I know you probably wanted to provide some kind of chronological backstory, but out of everything you wrote, this was the most important part.

It's very worrying and it looks like she's on some kind of reckless journey into self-harm. I'm afraid that other than locking her up or getting directly involved with in in a way that would distance her from you, there is not much you can do :(

aerisgainsborough · 09/01/2026 15:47

Icouldwriteabookonmydisastrouslife · 09/01/2026 14:08

I have no advice but I think some posters are being harsh considering you’re ND . Please have a bit of empathy for OP . My family are all ND , we don’t always see the world like other people and we can’t understand it as quickly as others.

💐 Hope you’re ok . Maybe take a step back and rebalance your brain for a bit , tell her you care but you can’t be there for her right now . You need to concentrate on your own wellbeing,

Thank you, I appreciate it. Boundaries are really hard and it’s something that I’ve always struggled with. I’m doing my best and don’t always come across well. I am genuinely coming from a kind and loving place. I just don’t want my sister or her husband to be sad.

OP posts:
RampantIvy · 09/01/2026 15:48

surreygirly · 09/01/2026 14:04

Mind your own business

That wasn't very helpful.

Tell your sister that you don't want to know what's going on in her life right now, she is an adult who can deal with her own affairs and you tell your parents and the rest of the family to speak directly to her if they want to know what's going on and stop involving you.

I agree with this ^^

@aerisgainsborough you need to tell your sister that you aren't interested in hearing about her love life.

MolkosTeenageAngst · 09/01/2026 15:49

I don’t know why you think your sister has BPD when you are a ND family, sounds like she is also neurodivergent to me. I have autism and ADHD and was diagnosed with EUPD (formerly BPD) initially, took several more years before I was actually recognised as being ND.

pikkumyy77 · 09/01/2026 15:50

aerisgainsborough · 09/01/2026 13:56

She tries to make it my problem when she’s telling me the whole sordid story, crying because she’s left her husband for a much younger lad. Then asking for advice on how to ensnare him and should she send an anonymous message to the lad’s partner exposing their affair. Then she’s swearing me to secrecy and then fucks off down the other end of the country to play happy families with her in-laws. I can’t cope with things like this, my brain short-circuits. Maybe because I’m autistic, I don’t know. I’m normally resilient but this was too much. I feel how I feel.

Just refuse. Hold your hand up, palm forward, and say “No” very forcefully. Whether this is in person or over the phone. Signal to yourself and to her in this way that the eldest sister shop is closed. Do the same with your mum. Just say “its none of my business.”

Pricelessadvice · 09/01/2026 15:53

Not your circus…

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