Haha!!!!
You just described my psycho ex! She only went for guys who treated her horribly, and then when we started dating, she became absolutely psychotic. She put me through hell. Then after I dumped her, she called me 6 months later and we were kinda hanging out again. Then she decided she wanted my friend so I said some pretty mean things and that was it. Then a year later she called me up again saying she was really really sorry and I'm the only guy she'll ever love. I told her I have a girlfriend, and she was totally acting all upset and stuff.
The whole time I was with my now ex girlfriend, my psycho ex tried to get me to get back with her, and once I was single again, she rarely talks to me!
I kinda wish I had cheated on my more recent ex with my psycho ex though because in the end my recent ex burned me, but I got my revenge by hooking up a few times with some girl that she was totally jealous of and suspicious of because this other girl was always trying to get with me too.
I'm a pimp when I'm taken, but I'm a loser when I'm not!