Cheating

I would have to tell her! It may damage your friendship but she'll thank you down the line. It would be her choice to stay or leave... Have you decided what you are going to do?

i would tell her cus who know's if he's going to run into a disease....and id treat him like the jackass that he is.....that is unacceptable

I think I would let him know I knew about it and tell him if he doesnt tell her I will. But I would definately tell her even if he says he already did. I have been in a similar situation except I was the one being cheated on. I was so mad that all the people that knew about it didnt tell me. They let me keep looking the part of the fool. It's no fun to be cheated on and it hurts like crazy when you find out. My mom was the one who told me and I didnt hate her for it. I hated him for cheating.

If you don't tell her then you have to wonder what her reaction will be when it all comes out and she wants to know why you didn't tell her...tough situation

I would let my friend know. Although she may end up being mad I would still tell her. It is almost a no win situation. SHe will be upset either way. But I would tell to clear my mind.

Blackmail is the only course of action

Depends on how well I know this friend. If I hardly know this friend, I prolly won't say anything, if not she/he won't believe me either.

I most certainly would tell a friend if I knew for sure their spouse was cheating on them. I have no tolerance for dishonesty!