To me it seems like he likes the idea and wants it "in theory" but may not be his interest in reality or is just confused about it altogether (which explains him trying & then backing off when he was really in the situation) so he's either consciously/ unconsciously avoiding it till the time he understands himself and his thoughts on the subject or maybe really waiting for some "right feeling" to do the deed (which is a slimmer possibility)

Honestly it looks like it has more to do with himself than you or the relationship. He values you & likes you and loves you for real but he's unsure of certain things in his mind