BIL's girlfriend cheating on him. WWYD?

[ThereAreNoMoreBiscuits]

Have namedchanged for this just in case anyone in RL knows my NN. For reference, I am not actually married to DP yet, so 'BIL' is not actually BIL, but it's easier to say that!

I was told this a month ago, by someone I assumed was fishing for gossip. The person who told me is known for her inability to keep a secret and for making something out of nothing. She didn't go into details with me and I didn't ask for any, so I dismissed it and basically forgot about it. I don't particularly trust the person who spoke to me and I didn't want to engage in gossip about a woman I happen to like and whom is a sweetheart to my DCs. We often go out as a foursome (me, DP, BIL and GF) and I was planning on asking her to be a bridesmaid at my wedding.

However, I now know that what was said to me is true. I have seen the GF with someone else (definitely with) and I know she had told BIL she would be elsewhere while she was with him. I am in no doubt now that she is cheating. I do not know how long it has been going on for and what the exact nature of the 'relationship' is (ie, whether it is a fling or something potentially serious, etc).

If you were me, WWYD? My instinct is to keep my mouth shut, pretend I saw and know nothing, and stay out of the whole thing. I haven't told anybody that I know yet, not even DP. I know if this was a straight case of seeing a friend's partner cheating on them, I would tell them in the kindest way I could, and I would like my friends to do the same for me if DP was cheating on me. But although I consider BIL to be a close friend, he is DP's brother and therefore I don't feel I can make the decision to tell or not tell without talking to DP. Though with that in mind, am I putting DP in an awkward position he doesn't need to be in if I tell him this? Then there's also the added bonus of actually liking GF and the DCs liking her too.

I really don't know what to do (if anything). I know if I were in BIL's position and I found out both that I had been cheated on and that my SIL knew about it, I would be horrified and I'd feel doubly betrayed.

Please help me decide what to do here!

Talk to the SIL and tell her that if she doesn't confess all, you'll be talking to your DP. I don't think you can really do nothing.

Sorry - that sounded really unsympathetic, and I am very sympathetic - a nightmare for you. But there's always a chance they'll get through this - couples do.

It didn't sound unsympathetic at all Hassled, it's a scenario I've run through myself. I don't feel like I can sit back and do nothing, I just can't see an option here that's going to end up with no one getting hurt, but that's what I keep looking for regardless.

I should mention BIL and GF are in a serious relationship and live together.

I would tell your DP and let him decide what to to about it - it's his brother after all.

I wouldn't go over DP's head and tell BIL, that's not an option I'm even really considering. If it was BIL that was spoken to about this, it would be DP doing it. I do consider BIL a close friend as well as family, but you are quite right Moo, DP's brother, DP's place to tell.

I feel like talking to the GF first, even though she is my friend, would be disloyal to BIL. My loyalty certainly is to him and by talking to the GF, I would be doing so to try to cushion whatever blow would come to BIL, not to save the GF's arse, IYSWIM. But I feel as though I would be going behind BIL's back (and I guess DP's as well) and I suspect he would be hurt that I spoke to her first, no matter my motivation for it. And I can only assume he would find out I had spoken to her if/when the cheating was exposed.

Sorry, I think I'm rambling here....

I agree with moomoo. Tell your dp and let him tell him. I think your bil should know imo and tbh your dp might be annoyed that you never told him sooner

I think tell your dp and decide what to do from there. I don't think you should keep it to yourself.

The fact that she has become your friend shouldn't sway you IMO OP. Your boyfriend (fiance? You mention that you're not married 'yet') is his brother, and therefore is family. That is where your loyalty should lie.

Yes sorry, DP is my fiance.

My loyalty absolutely does lie with BIL, no doubt about it. While there is a selfish part of me that hates how much this will affect the nice little set-up we have, I certainly regard BIL as the priority in this. I feel that if I was to speak to the GF, I would be doing so from the perspective of BIL's SIL, rather than the GF's friend (if that makes sense at all!).

General consensus is that I should talk to DP so he can talk to BIL?

Our family are in a similar sort of thing with my brothers gf, we told him she was cheating, he believed me (we are close and he knows I would never be malicious). A week later he had forgiven her and back together. This has gone on and on. He has caught her out himself and still they end up back together. However now we are drifting in our relationship, she wipes messages we send from his phone, he is hard to get hold of as will only answer or return a call when he is at work. A lot of damage has been done. I would proceed with caution. I always believe in honesty with your family - after all who else in the world can you be honest with if not them? But seeing how blame and mistrust can spread out from the couple and cause bigger rifts has surprized and saddened me. You should tell your DP but maybe let someone else be the bearer of bad news. After all there are no such things as secrets. Someone always finds out. You already have.

Actually thats a good point, what an awful situation.

No, she didn't see me. She wouldn't have expected to see me either. I was in a car she doesn't know and in a place I have never been before. I was picking up a friend and was sitting waiting when I saw the GF. I had sight of her for 10 minutes plus, there's no way this is a mistake.

While I can't really predict BIL's reaction to this, he has been cheated on before (although he never got iron-clad proof of it) and the relationship didn't survive. I can't see him forgiving his GF for this, though I accept entirely it would be his decision, and if he did choose to forgive her and they eventually put it behind them, I would not make things any more difficult for them than they would inevitably be.

I don't think I can really talk to her and give her an ultimatum to tell him. I may have gone that way if I didn't know BIL the way I do, but I don't think that can be a real consideration when the other person is family.

I have to talk to DP, don't I? :(

Yep, I would say the decision is ultimatly his. I know I would want to know if I were your BIL, but I would gear yourself up for your frienship to break with the gf. Obviously if they split, but also if they stay together it is quite likely she could blame you/accuse you of lying. I'm not trying to scare you off telling - I did and would again, just want you to be prepared. I feel for you life is complicated enough without getting caught up in someone elses mess x

There is no good option here, no matter what I do, someone will be unhappy because of it. But I ultimately do feel that if BIL was to find out in some other way, or that the cheating went on and on, he would be really angry that I had known.

I think DP will tell him without the hesitation I have had. He likes the GF, but he has much less of a relationship with her than I do, he is nowhere near as close to her as I am to BIL. I won't ask DP to hide that I was the one who found out, but I do agree that it would be better coming from him.

This is utterly crap. DS has a special name for the GF and everything. Both DCs love her. :(

You HAVE to tell your DP you have to, you have already kept it from him for too long. This is one of those secrets you tell immediately so he can decide what to do, whilst you sit back and do nothing you might as well tell her she is allowed to continue to take the piss out of your BIL.