Assuming that's his reason, and I hate to assume, I'll say, presuming that's the reason, then there you have it. It has something to do with each of you. His inability to express shows that he's having difficulty explaining his own emotion, which causes you to conject what his reasons might be. Since you aren't him, and you can't know his reasons, you can only know your own.

If you've been depressed, it's sad that the reaction of others is to pull away. What I think we need most of all during that time, is closeness. Some people just aren't ready to deal with it. Love yourself first in this situation, figure things out for yourself right now. His time will come, and, if you feel strong enough, you might even, in a kind way, help him to understand what's going on.