Scared

I feel him pulling away right now.  And it's scaring the hell out of me.

For years now, whenever we've had a good day, whenever we start to get closer, whenever things start to calm down and go in a positive direction, he freaks out and get scared.  And pulls away.

And I confront him and try to figure out why.  I try to get to the bottom of it and he pulls away more. 

It's been days since I've spoken to him and this doesn't happen.  I'm freaking out because I know what he's capable of doing to himself.  And while I have confidence that he's not off doing drugs or something stupid, the fact that it's been days is making me very scared. 

What is he so scared of?  Why won't he let this be something amazing?