Alright, she is really pissing me off!!!

Ehh..scary situation...why don't you try talking to the guy?? Get his insight on everything...what really happened and all that. If he DOES just go out with girls to sleep with them...then he's not worth it. But if he's really the sincere guy you think he is, see if he'll go out with you! And if your "friends" still say crap about him and talk behind your back, you might want to rethink your friendship. Hope this helps. Good luck.