A cliched question: Does he like me?

Hmmm well, I suppose it's too soon to tell, but to me, it seems like he's showing some form of interest. But if he has a girlfriend, that is no bueno. He could be bringing her up even though he's into you because it's a guilty subconscious thing. He feels the need to let you know he has a girlfriend so that he can remind himself that he's taken. But all you can do in this specific situation, is keep doing what you're doing girl. Doesn't seem like you're doing anything wrong to me.