His emotions are very difficult for him because he has learned that he is not special and went through periods where he was not nurtured. That does not mean that he is incapable of emotions but it would help for him to see a counselor. The best thing you could do for him at any time is to convince him that he would benefit from seeing someone who can resolve these issues. As far as the relationship, you are going to have to have a lot of patience He has had no role models to allow him to see what a happy couple looks like. Giving him space may help somewhat because he can reflect on his issues. I would email regularly though so that he has someone to talk to. Find out from him how much space he needs. Also what he needs from you. Work together on what he needs rather than instituting what you think he needs.
If this has been helpful press accept