What, I need help with this?

So me and this guy have liked each other for a lil while but we didn't want to mess up our friendship so we didn't date...well i never had the to ask him out and neither did he. He ended up going out with one of my friends ( Which didn't bother me until she broke his heart and he came to me crying then went back with her 3 times) When they were dating she'd be a B*tch to him. She'd flirt and feel up on other guys and just be mean to him. He finally had enough and they broke up, so i started flirting with him. Then at a fun raiser at my school my bff told him how i felt about him, cuz he wasn't sure. He felt the same way. His ex found out and she LEAD him on. And got him to tell me he didn't wanna be in a relationship with me after telling me bff he did. So when he asked her out she said no. He asked me out i said Yes. She found out, started crying and telling him she was in love with him. He tells me he wants me NOT her but from the other girl she says the opposite. And she told me she's been crying everyday knowing Me and him are dating. And she told me she's in love with him. Am i wrong for wanting to stay with him? He doesn't want her, so he says. I really do feel bad cuz i know i caused all this but i really like him. He tells me not to feel bad thi, that my friend brought this on herself. Btw ma and him have been dating cents Wednesday (4-20-11) and he has already kissed me.....Just someone help me understand this.