Catching somebody else's partner cheating is almost more excruciating than catching your own cheating because you actually have a choice not to deal with it.
It's not really a choice at all: eventually, said partner will be caught, and either you'll be confronted with the less-than-shocking news, or you'll get sold up the river by the cheater to make him-or-herself look good, or just twist the knife in your friend's back.
Having dealt with this way too often, the best method is really to confront the partner, alone, and lay it out: you saw them cheating, and they can either tell your friend, or you will.
I'm going to warn you now, almost inevitably cheaters think you're bluffing, and you are likely going to be forced to tell your friend. Sorry you're in this crappy situation, and good luck.
A very crappy situation. I would tell, because I would want to be told. If I found out my bf knew & didn’t tell me…, that will be more hurtful. Either way, you may lose your friend. It always seems to go down that way. You can do like they did in the movie The Dilemma & go for proof.
You're talking about your bestfriend. It's your moral obligation to tell her/he.
I have actually done this more than once(!) and I do not recommend you get involved. Believe it or not - they will NOT thank you. One friend actually married him anyway - divorced now but we will never be friends again. She actually knows I was looking out for her but somehow it does not turn out well... they have to find out themselves.
No good deed goes unpunished.
My best friend caught my ex cheating and she told me. I know how hard it was for her to tell me. There is no reason for her not to believe you if you are truly best friends and she trusts you. (Who makes up stuff like that anyway). Not to tell her is pretty crappy... yes it is probably hard and excruciating to actually bring it up in conversation but I know if my friend had decided not to tell me I would have been heartbroken to find out he had cheated on me and that she had KNOWN all along and never said a word. I wouldn't confront the partner - if he is shitty enough to cheat on her he is probably shitty enough to pull the wool over her eyes and make up some story explaining the whole thing as perfectly innocent..
Put yourself in her shoes
Be a friend.
I totally agree with you and thought that once as did my best friend once. It turns out everyone knew and I was one of the last to find out he was still seeing his ex all the time. So I took it upon myself to tell her as delicately as I could and she was great and appreciated me telling her at the time. Then she spoke to him and they worked through it and as things happen where emotion does not have to make sense somehow I became the troublemaker. Her family knew all along what was going on and did not tell her for a reason. Her mom was the one that told me she no longer wanted to have anything to do with ME! I was disinvited as a bridesmaid and as you can imagine the scandal at the wedding... Looking back, the dumbest thing I have ever done. She has to want to see clearly and it is hard to do that when you are in love. You want so much to believe in him. Everyone knew and no one said anything because they knew better somehow...
Another time I refused to be put in that position ever again so I went with her sister and she broke the bad news - I was there as moral support. The two sisters no longer talk and can longer be at the same family gathering together as a result. Neither sister will talk to me either. It's irrational but the sister broke up with him and just can not deal with either of us. And the sister that told her wishes I had stepped up and told her instead...
Dang, talk about shooting the messenger. I've luckily never been in this situation before and hope I never have to because it seems like a very gray line.
This is harsh, but your "friend" seems pretty stupid and you're probably better off without someone like that in your life.
I've been that partner that was cheated on. Quite frankly, I shot down everyone but two simply because they all knew and chose not to tell me. (Not literally, we're just not friends anymore.)
Those two who chose to tell me, we're closer for it.
Very sad to hear these stories about messengers being killed though. =/
If my friend came to tell me I was being cheated, I'd be embarrased as well as hurt. I'd want to be alone and concider things on my own. Confront my bf - and I know I*d be tempted to believe he's being wrongfully accused. It'd be so much easier to deal with. I know shooting the messenger is wrong, but I understand why it happens.
I'd scream red faced at my friend's SO if I caught them cheating. No words, just pure rage for causing the hurt to my friend and putting me into the situation where I have to tell my friend. I'd probably give him a chance to tell her, and if he didn't, tell her when he was around so she could see his reaction to the accusation.
Here's the thing...
I had to tell my MOM that my DAD was cheating on her. She didn't believe me until I showed her the picture I had that proved it. If I hadn't shown her that picture, she wouldn't have believed me (and I was 12 at the time).
IF you're going to tell a friend that their significant other is CHEATING on them, you'd better have PROOF to back it up. If NOT, then be prepared for a long hard road. You are more likely to keep them as a friend (and have them lean on you) if you have something substantial to show them.
CAUTION!
If you get involved in peoples relationships, THEY WILL MAKE UP. And YOU will be the a-hole.