Good luck - that would be hard task to do however, you could just simply try to talk to him and tell him it is not right what he is doing and not fair to his girlfriend. You have to know this could cause a riff in your relationship. You could also send an anonymous letter to his girlfriend as to not be involved and this way she will find out and you will be able to keep your friendship if you wish too.
be as honest and sensitive as possible and make sure that you have proof that the person was cheating
Your girlfriend's cheating
ypu can tell your girlfriend is cheating when she dont act like she used to act she acts all suspicious.she begins to blame u for cheating wen she the one really cheating.
Before asking your girlfriend or your friend if they are cheating on you it would be wise to follow one or both of them to see if you can catch them first. Check your girlfriend's messages on her cell phone or if you are living together then check where she has been on the Internet. If this is not possible then simply ask your best friend if he is cheating with your girlfriend and then ask your girlfriend. If they are lying often their face may turn red; they generally do not make eye contact; they may shift from foot to foot or leave the room completely or, they may argue loudly (over dramatizing) that they are not cheating.
You can tell for sure that your girlfriend is cheating, by catching her on the act with her lover.
They usually Wont Tell , but if you come across a friend that tell you & you wanna believe that friend cause your besties ect. Dont ! Cause youll end up getting hurt
of course. even if u dunt know her that well or u do know her well u must tell her it is better than letting her found out by herself and get upset u might be betraying your friend but he shouldn't be cheating in the first place
Yes you should tell her that he is cheating. Because later, it will hurt her if not told.
Tell her the truth. If you have been cheating, hiding it means keeping secrets, and for a relationship to last and work well you need to be open. If you haven't, you have to find out why your girlfriend thinks you're cheating, whether you did something that worried her or whether she lacks trust.
Here is how you decipher cheating: If your girlfriend knows nothing about it then it's cheating. If you have nothing to hide then tell your girlfriend this girl is a friend (if she is) and you're going to a movie. Hopefully you have a very understanding girlfriend. If this girl you are going to the movies with is of interest to you then be a man and break up with your girlfriend now! Cheating is ugly, it hurts your partner when they don't deserve it and it shows immaturity and dishonesty on your part. You know when you are doing something wrong!
One way to try to tell if your girlfriend is cheating is if she's refusing to spend time with you. If she has a new boyfriend she may want to spend less time with you.