Active discussions

Please or to access all these features

Talk
AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

Original poster

To believe sis(12) over SD(11)?

335 replies

Bestofgoodluck · 13/02/2025 19:08

SD is 11, have been with her dad for 5 years, mum is not involved. DP has to go away often for work and I work from home so look after SD while he’s away. This is mostly been fine, she has the option of staying with grandparents but chooses to stay with me.

I also have a 12 year old sister, our mum has quite a few problems and as I am older, she has stayed with me on and off since she was a baby.

They are completely different but have settled into a friendly but probably not friends relationship and there has never any major problems between them. I have been looking after both a them for about a week. They go to different schools and do different activities so don’t see each other that much but when we’ve been together everything has been fine and they both have seemed happy.

Sister went back to our mums today and SD came to me in tears and showed me some extremely nasty and embarrassing messages sent from my sister to her last night, I comforted her and said I would talk to my sister, she cried for me not to and said just not to make her see her anymore.
Sister said she had no idea what I was talking about and that there were no messages on her phone, was asking what they said and why she would do that, I’m 99% sure I believe her. I was already thinking the wording and content of the messages didn’t seem like things my sister would say and more likely that SD sent them to her self.

I feel completely torn between the two of them and can’t see how I can sort this between them or know who is telling the truth.

AIBU to choose my sister over my stepdaughter? And to say SD has to go to her grandparents if DP is away and my sister wants to stay with me?

OP posts:
PandaTime · 14/02/2025 15:11

He's a...clever man. Recruiting a vulnerable 21-year-old woman from a damaged home to be the unpaid nanny to his motherless 6-year-old.

Lyraloo · 14/02/2025 15:11

RebelStarChild · 14/02/2025 10:35

Are you OK?
Because she believes her sister she must secretly be her mother??

She literally said she would take her sister back to her house and stay with her there, how is she putting her sister before everyone and trying to kick the SD out?
As for wondering where her loyalty lies, what a ridiculous position to take in an argument between 12 year olds.
If her partner has an issue with her reasoning then he is more than welcome to look after his daughter himself.

Show quote history

But she is prioritising her ds against her ds! It’s op that is behaving in a childish manner. She’s not even giving sd the benefit of the doubt, it’s just instantly that she is lying.
im sure her dp would rather his dd is treated fairly and goes to her grandparents, in which case he’ll maybe start to wonder if there is any future in the relationship !

Lyraloo · 14/02/2025 15:07

Bestofgoodluck · 14/02/2025 10:35

DP does around two weeks away every 8 weeks, He’s done this since sd was small and since we’ve been together.
When he is home, he is home a lot more than most dads would be so it works.

You said your ds doesn’t live with you, so why for the two weeks your dp is away, can’t you let her stay with her mother while you’re looking after sd?

Lyraloo · 14/02/2025 15:06

Tiswa · 14/02/2025 10:48

So in those two weeks you are her major caregiver?

the problem is OP this is highlighting the fact it isn’t working - your SD attachment to you has meant she is jealous of your sister.

as you yourself said they are two very vulnerable little girls who need stability and you cannot give that to both of them you can’t.

and if you chose your sister (which you will and should) then your SD gets abandoned.

there is this idea that high schoolers need less parenting than toddlers - I have 2 it isn’t true they need the same but different and a pattern that was fine when she was smaller probably isn’t one that works now. The 80/20 ratio was good but now it isnt

Show quote history

Why should she automatically prioritise her ds? She has a mother of her own!

Madamecholetsbonnet · 14/02/2025 15:02

LilacLilias · 14/02/2025 15:00

It's not unusual for someone to have both sisters and stepchildren...

This is not a one off where OP is babysitting for a child, she is there with DP and SD 90% of the time.

It's not like she's an employee who is bringing random family members to the workplace, she's DP's partner, been together 5 years, it'd be pretty weird if she wasn't allowed to have her sister visit.

Edited - sorry I meant to reply to a different poster @Lyraloo who was saying it wasn't right to have Dsis there

Edited
Show quote history

I agree, except clearly it’s no longer working for the children concerned.

Dontbeme · 14/02/2025 15:02

Bestofgoodluck · 14/02/2025 10:35

DP does around two weeks away every 8 weeks, He’s done this since sd was small and since we’ve been together.
When he is home, he is home a lot more than most dads would be so it works.

Frankly he needs a new job, he is outsourcing parenting to his (I am guessing much younger) GF 25% of the time. I would no longer be providing childcare for him OP, return to your own home and redraw some boundaries in this relationship.

I think it is admirable that you are a safe space for your little sister but boundaries need to be placed here too. While you clearly love your sister is it helpful to her long term to be able to only turn to you? If you were not around what are her options, and by you being her safe spot is that actually preventing her accessing others services that could support both her and your mother? Is the relationship with your DM difficult or is it more complex reasons like mental health or addiction that your sister needs a break from? You don't have to answer but just something to think about in regards to your sister having other supports in place.

It seems you clearly love and support both girls but you have far too much on your plate from very young, so please take care of yourself in this too.

Madamecholetsbonnet · 14/02/2025 15:01

Lyraloo · 14/02/2025 14:36

Wow of course she can but she’s clearly been happy to spend 90% of her time at his house!

Show quote history

Yes she has been happy to do him this favour, but clearly this can’t continue.

It isn’t her responsibility to make childcare arrangements for her DSD, that’s her father’s role. She used to stay with grandparents before OP made the offer to support, so that’s one option the father has.

LilacLilias · 14/02/2025 15:00

Madamecholetsbonnet · 14/02/2025 14:24

Surely OP can maintain a relationship with her DP and with his DD without continuing as unpaid live in help when he’s working away!

Edited
Show quote history

It's not unusual for someone to have both sisters and stepchildren...

This is not a one off where OP is babysitting for a child, she is there with DP and SD 90% of the time.

It's not like she's an employee who is bringing random family members to the workplace, she's DP's partner, been together 5 years, it'd be pretty weird if she wasn't allowed to have her sister visit.

Edited - sorry I meant to reply to a different poster @Lyraloo who was saying it wasn't right to have Dsis there

Lyraloo · 14/02/2025 14:36

Madamecholetsbonnet · 14/02/2025 14:24

Surely OP can maintain a relationship with her DP and with his DD without continuing as unpaid live in help when he’s working away!

Edited
Show quote history

Wow of course she can but she’s clearly been happy to spend 90% of her time at his house!

Madamecholetsbonnet · 14/02/2025 14:24

Lyraloo · 14/02/2025 14:00

Of course it’s not irrelevant, it’s his house and his partner has obviously agreed to look after dd while he’s away. It’s her SISTER not her child that is obviously causing an issue, regardless of whose fault it is. Op should work out if she wants a relationship with dp and his dd or if she wants to look after and put her ds first.

Show quote history

Surely OP can maintain a relationship with her DP and with his DD without continuing as unpaid live in help when he’s working away!

Kingsransom · 14/02/2025 14:21

ForeverPombear · 14/02/2025 13:48

I don't see the relevance to that question?

Show quote history

I think it kind of is relevant as her age now shows she has been trying to step in to a kind of parenting role with her sister since she was 14, and is likely in a relationship with someone much older. A child that hasn't ever had clear adult guidance may do questionable things. You step up to protect your sister because it is what you have always done, but there seems to be a blurred line between sibling and responsible adult. I know you want to sheild your Mum but this situation is highly likely to get much much harder in the next couple of years. Be prepared to take support as you will likely be out of your depth. Take care of yourself OP.

UndermyShoeJoe · 14/02/2025 14:19

Either girl could be the jealous one if you go that route.

Dsd jealous is the sister coming into her home taking away step mums attention and time.

Sister could be jealous of dsd getting her sister as her step mum with her own useless mum.

The only way checking the phones will help is if day sister was texting a friend too at the same time or has since text a friend about what she did.

If either girl just grabbed the phone on a toilet trip and didn’t message anyone else it won’t prove who said what.

DivergentDilema · 14/02/2025 14:08

IC2211 · 14/02/2025 12:54

Sorry if you have answered this @Bestofgoodluck , but surely your sister would look at her phone in the morning and be "Eh? Why is your number at the top of my list, I haven't sent you anything" to your SD and be confused as to why she had a load of "sent" messages deleted

Wouldnt she say to you how strange it was and show you?

Yes, I don't understand this either.

I also would be checking your sister's phone. An 11/12 year old child should be having their phones spot checked anyway to keep them safe. I know she isn't your daughter, but by the sounds of it her mother isn't likely to be checking either.

diddl · 14/02/2025 14:08

If this isn't the option SD wants & she is the culprit then well that's just too bad isn't it?

Maybe if it doesn't happen that often that Op looks after her sister when her partner is away then things can carry on pretty much as they have been.

Op looks after her sister at her house, SD's dad makes whatever arrangements he made before Op was available.

Lyraloo · 14/02/2025 14:02

Dramatic · 14/02/2025 13:05

But SD needs to know that faking nasty messages is not on however she's feeling. If she is allowed to think that it's fine because she's feeling a certain way then that opens her up to doing all sorts of nasty things.

Show quote history

You nor op has absolutely any proof it was her! It could be either of them and op is jumping to conclusions because she is siding with ds.

Lyraloo · 14/02/2025 14:00

LilacLilias · 14/02/2025 10:35

SD is also not OP's daughter. And whether or not DP needs to be hosting DSis is rather irrelevant seeing as he is not actually there parenting, meaning OP is left to look after two girls who aren't hers.

Show quote history

Of course it’s not irrelevant, it’s his house and his partner has obviously agreed to look after dd while he’s away. It’s her SISTER not her child that is obviously causing an issue, regardless of whose fault it is. Op should work out if she wants a relationship with dp and his dd or if she wants to look after and put her ds first.

Original poster
Bestofgoodluck · 14/02/2025 13:55

I also don’t see the relevance of my age but I am 26. I understand that doesn’t quite make me old enough to either of their mothers but that’s not what I’m trying to be, I am still a perfectly capable adult.

OP posts:
ForeverPombear · 14/02/2025 13:48

Anonforthis58 · 14/02/2025 13:25

OP I’ve asked this twice now but you’ve not answered. How old are you?

I don't see the relevance to that question?

Anonforthis58 · 14/02/2025 13:25

OP I’ve asked this twice now but you’ve not answered. How old are you?

Dramatic · 14/02/2025 13:05

Lyraloo · 14/02/2025 10:31

Wow, that is an awful assumption. And even if sd did it, which I doubt, she doesn’t ’need dealing with’. This is her home if ds is causing problems and they don’t get on, it’s her that needs to clear off out of this child’s space. She is not the op’s daughter, as far as we know, and she’s not the dp’s responsibility to have in his home. She has a mother of her own, sd doesn’t and her father works away and obviously thought he could trust op with his daughter. Clearly that’s not the case, she’s brought disruption into his home and is now prioritising ds over sd. Totally out of order. If sd did do this, it’s maybe a cry for help, she probably feels pushed out of her own home.

Show quote history

But SD needs to know that faking nasty messages is not on however she's feeling. If she is allowed to think that it's fine because she's feeling a certain way then that opens her up to doing all sorts of nasty things.

IC2211 · 14/02/2025 12:54

Sorry if you have answered this @Bestofgoodluck , but surely your sister would look at her phone in the morning and be "Eh? Why is your number at the top of my list, I haven't sent you anything" to your SD and be confused as to why she had a load of "sent" messages deleted

Wouldnt she say to you how strange it was and show you?

Chillibeds · 14/02/2025 12:40

ThejoyofNC · 14/02/2025 10:54

Of course it's not the option she wants. She cooked up this little plan thinking she could get rid of your sister, and it hasn't worked.

The fact she's continuing to try and force the idea that your sister shouldn't stay anymore just screams guilt to me.

Show quote history

Me too.

Who wins if this plays out?
Your SD.
Be very firm and make it a non negotiable, you will be with your sister going forward as your step daughter needs to be completely separated from them.

If the phones were accessible to your SD then of course she could have text herself on your sisters phone nasty messenger and then delete them. Not difficult to do.

Your sister needs you and she should be where your loyalty lies.

SD goes to her grandparents.

Glittertwins · 14/02/2025 12:30

Missed that bit, thanks @Madamecholetsbonnet

Madamecholetsbonnet · 14/02/2025 12:12

Glittertwins · 14/02/2025 11:09

I don't think you can effectively throw your SD out when her dad is away - whose house is it?

OP has her own home, but in order to support her DP she has been staying at his with DSD when he works away.

Clearly this is no longer an option as DSIS needs a safe place to go at short notice. Hence the posts suggesting SDs father makes other arrangements and OP no longer moves into his when he’s not there.

jannier · 14/02/2025 11:47

Bestofgoodluck · 13/02/2025 19:27

Sorry if I didn’t make it clear.
They are text messages from my sisters number, shown to me on my SD’s phone.
Both girls were staying here last night, I was believing that SD had sent them to her self from my sisters phone while she was asleep.

So you automatically side with your sister.
Phones on landing obviously isn't working why are they not downstairs?
Both are children yet your not treating them as such.
I think I'd be doing some family building bonds time rather than separation