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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

To tell my brother in law that my sister is cheating ?

190 replies

Aurelie20 · 06/03/2020 19:19

I have been reading on this forum for months and now I have something I need advice on..

My sister and I are very close and always been. She is perfect ,have a perfect house , perfect children and a perfect husband... After my marriage ended I moved in with her , and since he works night shifts I spent a lot of time with him and the children during the day.

She told me about 2 weeks ago that she has been seeing a man for roughly a month and thinks about leaving her husband but wants some time with the other man to be sure. I AM SO SHOCKED! I can't believe her. She has a perfect man that loves her and does everything for her.

I am close to him and cannot at look him in the eyes now. Especially since he always talks about her. I feel like telling him because he does not deserve that. But at the same time I don't want to lose my sister. She trusts me. What would you do.

OP posts:
WinterCat · 07/03/2020 19:02

@itsallthedramaMickiloveit of course I do. Why wouldn’t I when it specifies this in the OP and I can read? I don’t approve of affairs either, before you make yet another incorrect assumption.

Aurelie20 · 07/03/2020 20:35

I am babysitting her children , while her husband is at work and she went on a romantic date with that new guy. The issue is that her children can talk so can tell the dad she was not there. So I am supposed to "coach" them for tomorrow lies.

OP posts:
lovepickledlimes · 07/03/2020 20:38

@Aurelie20 now she is getting the kids to lie???? that is not on. She really needs to come clean.

Aurelie20 · 07/03/2020 20:40

I decided not to say anything and let her do what she wants to do. And again I am not after her husband , I can't even forget my ex... and she loves to remind me that I "failed" my marriage and never got pregnant. She is 16 years older than me so I used to put her on a pedestal. I am struggling with my own love life. I do not want another man than my ex. It just shitty to have to lie to him,
Even if he isnt perfect or they have marital issues I feel bad he seems nice , and I have known him since I was a child. So I wish I did not know

OP posts:
Aurelie20 · 07/03/2020 20:42

Lovepickedlimes yes 2 kids who are under 10

OP posts:
Smileyaxolotl1 · 07/03/2020 21:00

Wow aurelie I feel so sorry for you.
Please don’t coach the children at all.
How dare she put you and her kids in this position.

SudokuQueen · 07/03/2020 21:07

and she loves to remind me that I "failed" my marriage and never got pregnant

Oh no no no. Call the bitch out on it. Tell her husband. Let him get his ducks in a row and kick your sneaky, shitty, bitchy, lying sister out.

You're actually still going to stand up for her when she said this about you?

And she wants you to teach her kids to lie? Fuck that for a laugh. Tell her husband when he comes home. That guy and the kids are the victims here. Sorry but your sister is a shitty person, how dare she say that to you. Considering what she is doing? What a tart.

CatherineOfAragonsPomegranate · 07/03/2020 21:11

I'm really pissed that she's doing this stargazing tawdry romance and trying to include you when she knows your're still yearning for your ex and recovering from the upheaval of your own broken family.

It must be upsetting to have to countenance possibly losing another family member (BIL) and another marital breakup. Quite a stressful thought.

She doesn't care about your recent trauma though.

Unbelievable how selfish affairs make people.

DontDribbleOnTheCarpet · 07/03/2020 21:12

and she loves to remind me that I "failed" my marriage and never got pregnant.

Maybe you are her best friend. It sounds like you may be her only friend. She certainly is not any friend to you. I'm so sorry.

SudokuQueen · 07/03/2020 21:15

She doesn't care about your recent trauma though.

Yeah this. She, like all cheaters, only cares about herself. She is a shit person.

I'm angry on your behalf, how dare she say that you failed your marriage because you didn't have kids. Ugh. Sick person.

dodgeballchamp · 07/03/2020 21:48

I love how everyone’s suddenly changed their opinion now the sister has been revealed to be a total bitch! 😂 move out OP and tell her you won’t babysit if it requires telling the children to lie

justasking111 · 07/03/2020 22:15

I would have refused to baby sit the kids. That is truly awful she should not put you in this position. Let the chips fall where they may now. Do not coach the children.

CJsGoldfish · 07/03/2020 22:17

I love how everyone’s suddenly changed their opinion now the sister has been revealed to be a total bitch!

I love how the OP ramped up the sisters behaviour/attitude after being called out on her jealousy in the original post and lack of total support.
Could count on the sister becoming worse and worse as the thread went on depending on initial response 🤣

lovepickledlimes · 07/03/2020 23:10

@dodgeballchamp I find that so funny too lol as if it is ok to cheat as long as you are a good person lol. my biggest romantic movie pet peeve is if one is in a relationship and has an affair with the love interest but it is ok because the partner is mean and the protagonist is a good kind person.

saraclara · 07/03/2020 23:29

I love how everyone’s suddenly changed their opinion now the sister has been revealed to be a total bitch!

Well of course. It's one thing for OP's sister to be having an affair. It's another for the sister to ask OP to lie for her (and babysit her kids while she's with the other man.

Of course that changes things.

I still wouldn't want to be the one to tell the husband though. I'd simply move out.
OP, do you have anyone else you can stay with?

TabbyCatPaws · 07/03/2020 23:34

OP you need to move out, you are too involved in her life. She doesnt sound very nice, but as she is your sister I'd suggest you move out and let her deal with the affair, itll come out sooner or later.

If you tell him then she will probably never forgive you. He will find out soon enough, these things always come out.

SudokuQueen · 08/03/2020 00:00

To be fair, I've only just seen this, and would have said tell the husband regardless. Cheaters are scum in my opinion, there is no valid reason to cheat. There's always another option. And there's no reason to stoop so low.

Ops sister is scum. For cheating, for what she said to her sister, and for using her children as pawns in her romantic love story.

lovepickledlimes · 08/03/2020 00:40

@SudokuQueen feel exactly the same.

PotholeParadise · 08/03/2020 02:07

Move out. Keep entirely out of everyone's way until you have moved out, so you're not even tempted to say anything.

After you've moved out, you can revisit the issue and properly express how you feel about it to your sister, but move out first.

BoomBoomsCousin · 08/03/2020 02:45

That's a hard situation for you Aurelie20. I agree with those saying not to tell her DH, a sibling is normally worth a little preferential treatment even when it is unfair on others. But I also think you have every right to refuse to be an alibi. It's fine to tell her that she needs to keep her ongoing activities as much a secret from you as she does from her husband.

You are judging her (sounds like she's been judging your love life too, so she has little grounds for complaint on that score). It's OK to have moral concerns about what she's doing and to let her know it doesn't sit well with you. But it would probably be good, as a sister, to listen to why she feels the pull to do this. Not to let her use you as part of her fantasy talking to you about how great this man is, but possibly to tell you about how her marriage isn't working for her. Because you have a picture of it as perfect, and it clearly isn't perfect from her perspective. It may just be that she just isn't an "all life" type of woman. But that's difficult for people to admit in our society where staying together, especially when kids are involved, is seen as "better" than admitting you've lost all the spark and don't want to stay anymore. It might be something else. If you're capable of it, giving her some space to talk about this side of things might be good for both of you.

NoFucksImAQueen · 08/03/2020 06:08

She loves to tell you you failed your marriage? And you look up to her and say how lovely she is?

BloggersBlog · 08/03/2020 08:58

woooohhh some mahoosive drip feeds there OP! Another thread that is almost unbelievable

YellowHighHeels · 08/03/2020 09:22

Sorry if I've missed this, OP but do the kids know she was out with the other man or just that she wasn't at home? If the former, it is disgraceful to be involving them in the affair and teaching them all sorts of weird dysfunctional ideas about relationships.

At the very least she needs to protect her children from being in this position.

If the latter, why do they need to lie? Sounds like DSis is loving every minute of the drama though.

You can't be complicit in making the kids lie. What kind of a lesson is that? That is not the same as just staying out of it if she was being discreet.

Keep your head down until you can move out in 3 weeks if that is the absolute soonest you can do so. Can't you spend a week with a friend/ other family?

TheNewPlagueIsComing · 08/03/2020 09:26

All of you sound ridiculous.

WeAllHaveWings · 08/03/2020 09:28

Tell her, yes, you are judging her, what she is doing is wrong..

Tell her you will not lie for her or be her alibi so she is not to ask you to babysit.

Move out.