Should I tell him?

Ya know, everything a person does comes back to them, in one way or another. And it's very possible he'll think you are just trying to get back at him or something to that effect. Don't get involved in his current relationship in ANY way; he'll only resent you for it. Be the better person here. It seems as if you already are. :)

I would NOT tell him; and trust me, he'll find out somehow, some way. If he chose a person like this to be with, he'll definitely find out in due time that she is like she is... someone who is a cheater.... IF that is truly what she is like.

I know how it feels to be in your position. GOOD LUCK! :)

If you have to ask the question, then the obvious answer is to tell him. You clearly are a person with a good conscious who is unconsciously attempting to revenge someone who probably hurt you in some way in your past.

By telling him, you are being a better person by not stooping to the level of the other person, but at the same time, he may think that you are playing some sort of trick on him, causing more feud in your relationship.

Ultimately the decision is up to you. Do you want to be the better person and risk having more drama in your life, or do do you want to stoop to a level that you frown upon on other people. Please tell me what you choose to do in the end.

As tempting as if is to tell, don't, her true colors will come out and he will see for himself. If you do tell him he may think your just trying to cause him trouble. On the other hand you could arrange things secretly some how so he actually catches her in the act.

I doubt he would believe you (you might be suspected of having an ulterior motive for sharing this info). Since you didn't see this yourself (more's the pity) it would be hear say at best. What goes around comes around...move on with your life. Good luck!

I wouldn't tell him. If he confronts her, she'll probably lie about it and turn it around on you, saying you're just jealous and trying to get him back and he'll probably believe her. Just sit back and watch though, because what goes around, comes around.

tell him but he'll get angry at you and think you're jealous. then he'll stop talking to you but he'll find out about his gf cheating (they always will). but at least you told him.

i would say KARMA :) and laugh.