Complicated guy

I'd like your advice on this. I met a guy online, after being single for quite a time, who has been in a relationship for 4 years now. We were friendly at first, so he admitted he cheats as his girlfriend does not complete him. Something tells me that this guy was pretty hurt in the past, and somehow he ended up being sort of like a free spirit, with no emotions attached. We later met up, we made out, and he admitted the sexual attraction was insane. He claimed that it would be nice if I was his girlfriend instead, and that he wanted to break up with his current relationship. I told him he should leave me out of this, and do it for himself, where he agreed. Now the weird thing is, after we made up he got a little defensive and he said "that's the one I want to marry", speaking for his girlfriend. That caught me by surprise, and I just couldn't forgive myself for meeting up with him. He later explained that he got "scared" and that he really liked me, so a lot of wrong things came out of his mouth. I must say, I don't like coming second, so I was a little bit shocked after him being so disrespectful to me. I asked for my friends' advice and they ALL told me to get out, and I do agree with them. Something keeps pulling me in though, I want to see this through. I know he's a liar, a cheater, and nothing will stop him from doing this to me as well. I read something about a "wounded bird syndrome", what do you think about this? Is it true? Why do I care so much? Why do I want to fix things and make it work? There are so much better guys out there, and I consider myself quite attractive. It keeps me up at night, and I don't want to annoy him by sending him messages. It makes me feel sick, and my mood is crap right now.

girls like bad boys but its bad for you,forget and move on

do yourself a favor and let his other girlfriend keep him. There's no future with this guy.