An interesting note...I am from the same city in CA as you. I am a little alarmed by his calm behavior to you wanting a divorce. Perhaps people react to the reality of divorce differently, yet I begged and begged my ex to stay for the sake of our young daughter and stepson. But, I could not get her to acquiesce and we moved out of our home and lead to separate lives. But I digress and don't want this to be about me.
I want to acknowledge something. You're a rock star, since you are concerned with his mood considering your decision to divorce. I am really struggling myself and drowning and it just appears that my ex does not give 2 thoughts about my struggle. I am alone and on the verge of breaking. It is touching to me to see that you care for his wellbeing and ultimately his relationship with his daughters.
Alcoholism is a tough demon to beat, since I did it about 20 years ago. I have not touched a drop of it. I think most people become seduced by alcohol by trying to escape something mentally. Alcohol numbs the mind to suffering. I know this, since it was why I used to drink. It was a nice escape.
So here is my dilemma. Why did your husband drink? I assume it was something he was escaping. I think you said anxiety, but I feel there is a deeper reason. Something hidden in him he is trying to absolve. I am a little concerned with his nonchalant reaction to your decision. Something just doesn't add up to me. Perhaps I am assuming too much. I am sorry if I gave you added concern...
--sarc