Should I tell my girlfriend that her boyfriend is cheating?

Hmmm, I'm a little confused here... Is she your best friend or your girlfriend, as in you two are in love and in a relationship? If she isn't your lover, then I think it's okay to not open the Pandora's Box and probably it's best for her to find out herself. But if she is your girlfriend/lover and she already broke up with her past boyfriend, then it doesn't matter if her ex-boyfriend is seen with his ex-girlfriend because whatever he does should not matter to your girlfriend anymore. Hope that helps. :)

Well, you are not quite sure that the boyfriend is cheating, only you saw that he is talking with his ex. Maybe it would be better to ask first a hypothetical question? Like "If you see your friend's partner talking to his or her ex, would you tell your friend about it?" She'll get a clue. She can either answer that she wants to know or not. It's bad to jump to conclusions. it might have been just a harmless conversation between the two. Better yet, her boyfriend might have already told her about it so there is no point in keeping it secret. When I talk to my ex boyfriend I always tell my boyfriend about it right away and he understands.

Ofcourse you should tell her,that is what friendship is all about, helping each other.Actually if she finds how somehow that you knew that her boyfriend is unfaithful then she will feel bad ,may be she will be upset from you too.You will be doing a great favor to your friend if you tell her.Best wishes.

Before doing any drastic move, try to find out what is really going on with her boyfriend and his ex. If they are having a relationship, then maybe, you should talk to the guy first and ask him what really is going on and what as lead him to be doing it.

If this happens on me, I would rather my friend tell me first, but what she/he says should be based on the premise that my boyfriend and his ex have really did something that only lovers would do. Otherwise, I would oppugn and criticize my friend and our friendship may get suffered. So my suggestion is before you tell your best friend, you should investigate what the real relation between her boyfriend and his ex. Are they just pure friendship now? Or, you can inquire your best friend about the situation she have known about her boyfriend and the ex by means of a euphemism.

For me, If I'm in your situation, I will tell her. Yes it will hurt her a lot but think about if she marries that guy..

This type of subject should be treated with great care. You should not be blurting out unless you are definitely sure that the guy is cheating and that you have a concrete evidence. If you decided to tell the girl and you were denied by the guy, you are risking your friendship with your best friend. Hope this help

I think you must tell your friend about what you know so that if your friend was being cheated by her boyfriend it will stop early.

In this case they are not married so this may not be relevant, but I have heard about cases where the wife knew the husband was cheating but pretended not to know, so friends who did not realise this and tell the wife actually ended up making the situation worse since she could no longer pretend. There was even a case where the friend saw the husband going to a hotel with a woman, called the wife to come quick and catch them, and was instead scolded by the wife for "cooking up lies to try to break up their happy marriage".

Hi, I think you should tell her. The new will come as a shock and it will hurt her. But that will be minimal to her finding out on her own or her finding out that you knew. It's a bad situation no matter how you look at it. As her friend you can try to break the news kinda easy and be there for everything else. Plus, bad new always come a little better when it comes from a friend versus a complete stranger. Good Luck!

If I were on your situation, I would tell her. What's the use of keeping it from when she'll come to know it sooner or later?? Yes, you'd hurt her feelings but it's better than prolonging the agony, as they say. Just try to imagine that your bestfriend is doing anything because of her beloved boyfriend while that guy is enjoying the time with someone else behind your bestfriend's back. How does it feel? But you better be sure of what you saw, confirm it first on my opinion. :)