Are you sure this moving in with him is a good idea? I mean, if he's already getting under your skin and you haven't even packed up, doesn't that tell you something?
Maybe you should try to be a little less defensive and compromise on the stuff you take if you move in with him. I have heard you say before that your room is a mess and that you have too much stuff crammed in there. Maybe he's just concerned that your apartment will end up looking like that too.
That's what relationships are all about, compromise.