Thanks for your replies.
The fact is I know he loves me. I don't take his drinking problem as a sign that he doesn't care about me. I realize that he has to want to make a change for himself, not for me.
Ever since I had the conversation with him I've asked myself if I'm doing the right thing. I've wondered if I should have just broken the whole thing off and told him I'm here for him if he wants it as a friend. I know full well I can't change him. A couple of times when he was on a bender he asked me if I would "cut him off" when I thought he'd had too much. I said in no uncertain terms that wasn't possible. I can't determine that for him. I'm not his mother and I don't want to be. Furthermore, while I know that that would be at his request, he'd grow to resent it. I'm not taking him to raise. If he doesn't know when he's had enough then he shouldn't even start.
The thing is I love him and I'm having a hard time just throwing someone away because they're flawed.