Hi there, Percygirl - welcome here
This is really strange but it looks to me that he's pretty confused. He doesn't know what he wants I think. He's NOT SURE he loves you but if you'd move out you'd make the choice for him: decision, so that's where he's afraid of probably.
I don't know how old he was when he started to go steady with you, but it DOES happen that guys (but also girls) that start dating young start to ask themselves questions after a certain period of time - more because of the doubt that maybe they've missed something so they can't compare, than it is really doubting the feeling towards the partner.
I don't know if you should bother to make it work. It all depends on how you're together. Small things can tell a lot.