I think I'd be inclined to go to Al Anon. While I know very little about it, I do know that my wife went there for quite some time to learn how to deal with my drinking issues, and she says that she has greatly benefited from it. There's obviously no easy solution here, but unless your husband is abusive or if you're seriously feeling threatened in some manner, I tend to think it would be best to fully understand the situation before making a decision you may regret.
EDIT: Just upon thinking about this, from the way you describe your husband's actions, it most likely appears as though he does indeed have a drinking problem and that he is indeed an alcoholic. Most importantly, though, if he's generally a good man, and if he seriously wants to quit - this is an absolute MUST - I sincerely believe there really is hope for the two of you. But first, you'll need to fully educate yourself in how an alcoholic behaves before you'll fully have the capability to provide him with the kind of support he'll need from you. I just know that my wife hung in there for me, and I'm very thankful she did.