It sounds like a real internal fight going on. He want's to let that wall down but, doing it is going to hurt, he is going to need to take more than give in you relationship when he does, for a while. It doesn't sound like your relationship is in a good place for that to happen. So, he's escaping the only way he knows how to escape - in a bottle and by pushing you away.
I would guess that much of that is almost instinctive and not something he plans, he just does it because he doesn't have a better way to deal with what he's feeling.
One on one with his T, and getting your relationship more secure for him will help, I think.