Marina,
There's tons of literature on blackouts aka drug related amnesia. Yes, it's medically a form of amnesia! Which basically means that your brain can't or won't create long-term memories out of the little short-term memories it records as it's rolling along. I have been fascinated by the whole phenomena for a long time. I'm fascinated by amnesia in general.
I had my first (not last) at 20. I am also over 30. This is pure opinion I kinda cobbled together: I think blacking out is a sign of damage done to the brain by long term abuse. Most of us have basically beat our internal organs like a pinata. The brain has to perform so many different functions, it can only take so much.
Especially for us 30+, our bodies become less reliable even when treated well, let alone while drinking poison.
With continued alcohol abuse, how your brain will perform while intoxicated becomes volatile and impossible to know in advance. You won't know. It's like trying to figure out why I got on the elliptical for one day for an hour and felt amazing and the next day I had to stop after 30 minutes, even though I got the same amount of sleep, ate the same breakfast, etc. Sometimes my body can handle a whole bunch of stress, sometimes it can't, and I really can't predict why. I hope that makes sense,
My advice- DON'T try to figure out what you did during your blackout. Don't inquire. If you feel comfortable kindly asking friends/family to not tell you, maybe do that. Seriously, that isn't going to help.
You might want to think about marital counseling. Personally I couldn't live with a drinker, or even date one, I don't care if they only drink one, I don't care if it's not fair, don't care, don't care, don't care. Now, he might need to really understand how committed you are, which might mean you starting some sort of program. He might be carrying some kind of anger or resentment that needs to be addressed. But I don't think it's acceptable for him to drink in front of you.