I am in a very similar situation. I am in love with an alcoholic. I was like you--tried to control the drinking and it drove me mad. The first thing you have to realize is that you CANNOT control anyone. Even if we think we're helping, or doing it for their own good, we cannot control them. Good for you for going to therapy, maybe more will come out of it than just setting limits for the business. You need to take care of yourself and your problems--it's labeled "co-dependency." If you don't take care of you, you will keep making the same mistakes over and over again in your relationships, in fact, this may not even be the first time this has happened for you--loving someone with a problem--an addiction, a mental issue--something you felt compelled to "fix." Looking back at myself, this wasn't my first. But it's going to be my last. As far as he goes, he has to realize that he has a problem, accept it, and want to change. Only he can do that for him.
