there is nothing stopping him from being with you if that's what he really wanted. i think he just likes having his cake and eating it, too. plus, he's obviously got some (stupid) boundaries where he believes that by not "open mouth" kissing you, he isn't really cheating on his gf. however, he is still cheating on her both emotionally and physically (touching you affectionately and closed mouth kissing). even if he did decide to break up with his gf, chances are you'd end up in her shoes eventually. how will you feel down the road if you're together, and then you find out he's having the same kind of "friendship" with some other chick that he's having with you now?