Dina--I'm relatively new to SR so I'm no expert, but I can get a sense of why your situation is so troubling to you. I will just respond as a long-term wife.
If my husband suddenly took on a project of this magnitude that involved real spiritual development and which did not include me, I would be threatened. In fact, I know my husband is somewhat threatened by my involvement in SR and my very slight involvement in AA. He too does not think I am an alcoholic and encourages moderation rather than quitting.
So I'm trying not to change his routines, which includes a lot of time in places that serve alcohol, because I do not want to exclude him. This makes things hard for me because I am seriously tempted, and I have caught flack on this forum for being around alcohol, but I've said from the outset that I cannot up and change his whole life.
I mention this to you because your husband really seems to be acting independently. Now he has to take care of this problem (as he perceives it) on his own, but your life is involved too. So, if I were you, I would leap on in. I would not argue with him about it but would tell him that he had hid it well but you believe him. I would ask to go to meetings. I would join alanon.
It sounds like he's going through something--alcohol or personal related--and if you want to sustain the marriage, you had better go with him. My husband's mid-life crisis is that he has decided he's a karaoke star. He's not. I go with him.
Even if you just go shopping during his meetings, be there. If there's something you don't want to find out, you'll find it out. If there isn't, you will be supporting him in this new part of his life.
I'm not a big AA fan either. Doesn't matter. If he wants to be a Budhist and I want to stay close to him, I'm going.
(We've been married 28 years too!)