Things were going well then you met this guy, and he cooled off considerably. Everyone else who's talked about how he's probably grappling with coming out may be right, but there's a chance the chemistry just wasn't there, and he didn't feel it. That's not to say you're not attractive, just not attractive to him.
Regardless, it sounds like you've expended enough effort pursuing him while he hasn't shown any real interest (doesn't respond right away, and when he does, it's more or less to placate you).
So if you want my opinion, it sounds like he's just not into you. Best thing to do is to ignore him, IMHO. If he is into you, let him make the moves for a change. If not, you need to move on anyway.