Dude, that would make me mad.. like you're talking to her and putting in tis much effort and then she goes off and screws a random dude and tells you about it? Seriously.. show her no mercy.. and by that.. tell her you dont approve and want nothing to do with her.. maybe friends... Then she'll beg for you to be all in her.. If that doesnt work.. WHO CARES.. shes a bitch :]