All of a sudden won't give me a key to his place?

Its sounds to me that he may just already know something about the relationship that the two of you have that you may not be aware of. Its possible that he doesn't completely see his future being with you. You should definitley ask him if that is a possibility. If you have a child together, have lived together in the past, and he is now moving into a place by himself and is making it clear that it is his only by not offering his key, he may be unsure if he wants a relationship with you now or in the future.

Bottom line. You may want to make things work because he's the father of your child but he's definitley not as into you as he should be. And he sounds very immature. I'd tell him living together isn't going to work either and that you want to date someone who makes you part of his life. Only dysfunctional men 'are hard to catch' Mr. Dave, and who really needs one of those? There are plenty of fish in the sea and you should be with one who really wants to share his life with you.

he probably figures you two are gonna get together and this is his last chance to see what being on his own is. he's probably just thinking about having a little space before he jumps into the role that is in store for him. don't freak. if something becomes fishy then worry. its too early now.