I'm concerned about the fact that you do not want to see him when he hasn't had the beers. Also, the fact that you don't live with him could make it easy for him to hide the aftermath of his drinking. You see a very clean house. Like you said, maybe he is very much able to control other aspects of his life. He may even have an issue with control - like an obsessive compulsive disorder. I dated a guy for years who was OCD. He was very neat, but also had a problem with porn addiction. It was like he was very wound up and perfect, and the addiction was the only way that he could let go.
Your bf has even mentioned that he has a problem and he wants to stop. I think you should take him seriously.