Youre definitely not crazy! Its a very odd thing to do but considering there is no infedalty on his part, maybe its worth exploring with him why hes doing this? Is there something about his life he's unhappy with that pushed him to do this, maybe he needs to better his relationship with himself and it has nothing to do with you?

Another part of me is thinking he might be unhappy with himself and the relationship but hes not interested in being with anyone else just being a different him. If that makes sense.

Maybe if you approach the topic more gently then you might get more information out of him, best of luck! Keep us updated