my girlfriends best friend cheated on her boyfriend two times. Should I tell him or leave to be?

Stay out of that crap. You don’t want to be involved in a bunch of he-said,she-said crap. Men shouldn’t gossip!

not really your business. It been my experience that people don’t really appreciate unsolicted advice especially from a person they are not close to.

well it depends.

do you want to be a good friend, or a bad friend?

If you play out the scenario, there’s no way for you to not get in trouble with at least one of the following: your girlfriend, her friend, the boyfriend. Most likely all three will be mad at you.

mind your own business

Tell him. Its man law

think about what all the possible reactions to this will be, and ask yourself if you want to be in the middle of that.

If there was a way to let him know anonymously in such a way that the evidence doesn’t give your identity away, I would think that would be the way to go. Otherwise you’re going to spend a LONG time on the couch if you get involved.

stay out of it.

If you don’t talk to them on a daily basis your not good enough friends with them to do this.

It’s not your business, unless this guy she cheated on is your best friend. and I’m guessing you wouldn’t even know this had occurred unless your girlfriend had told you, so you’d be betraying her trust as well.

Stay out of it.. Unless he’s a friend of yours you’ll just cause drama between you and your girlfriend