You keep asking what is wrong with YOU, instead of asking what is wrong with HIM? I mean, he has a history of this behavior, don't forget he walked out on his first child's mother too. (It might be VERY interesting to talk to her and see if he was still involved with her when yo0u and he first met - I know he told you one thing, but he could have been lying. )
He's really not shown himself to be a good reliable man, not just in relationships but also in work etc. So why are you worried about whether YOU measure up? You should be asking yourself why you settled for a guy like HIM.
