Most Helpful Guy
The women's commenters are on the money. The guy's immature. Unless you drop him, he's not going to stop being a pain in your ass. This is the kind of man your guy friend invites to the bar who spends the whole time crying about all these problems he's caused for himself. My condolences for being the unfortunate woman he's currently fixated on.1
Most Helpful Girl
This guy doesn't know what he wants. He only wants you when he's 100% sure he can't have you (when you are in a relationship or when he is in a relationship). When you are available and ready and he is not bound to anyone either, he changes his mind and has second thoughts because there is literally nothing in the way that could stop it. So basically he is a drama queen.
No matter how much space and time you'll give this guy, he'll be eternally lost and confused about you. I think it's best for you to keep your distance and forget completely about him. Don't even keep in touch as friends because it'll be an ongoing push and pull where things get only more complicated. At this point he knows you well enough to know if you could potentially work out or not, the only thing that's stopping him is he not loving you. Forget about him and move on because this person has no respect for you and your time.2