I think there is an element of fantasy here. You describe the kind of relationship you want with him...not the kind you actually have. You talk about other people and how they feel about this relationship but no information that says anything about the relationship itself.
If your support could help him, it would have. Instead he is using. Without knowing it, you might even be enabling him, since you are giving him the illusion of normalcy.
It is clear in what you write that you know this is not going in a good direction. The best thing for both of you might be to cut off contact until he has a year of clean time. If there is something real here, both of you should be able to handle that. Then you have a shot at getting that relationship that you say you want with him.