First, let me say that as guy I do not think you are being too demanding at all. Personally, I think he needs to get his head out of his butt. At 9 months pregnant, you will be popping any day. What is going to happen when you go into labor, have a 2 year old to deal with, and he is out drunk in the bar with his phone off? I do not mean to offend you, but your husband is being an a**hole.
In my younger years, I hit the bottle pretty hard. By the end of college, I was a drunk. I had a drinking problem. I remember people saying that maybe I should cut back a bit and I remember my ex-fiancee suggesting that I hang with the AA crowd that gathered every Friday night at the restaurant she managed, but none of that mattered to me. I was interested in alcohol to ease the stress of school and the pain of a bad breakup. It wasn't until I realized that I had a problem did anything change. Nothing and I mean nothing anyone could have said or done prior to that point would have gotten me to stop drinking. After a moment of enlightenment, I cut back on drinking. Eventually I essentially matured and by 25 I had pretty much quit drinking all together (without help from the outside, a dumb move looking back on it now). I remember the feeling of being scared of AA because I would have to vow to never drink again. As stupid as it sounds, I was afraid to reach out for help because I couldn't bear the thought of living without alcohol. Pretty sick when I look back on it.
Your husband sounds a bit like me when I was a hard partier. I am shocked at a married man who would turn down sex from his wife where the only price he would have to endure is to spend the evening with her.
Plain and simple, he is choosing the bottle over you. As I am sure you know, if he is indeed an alcoholic, there is probably nothing you can do to change his behavior, he has to change it for himself and want to make the change.
The best I can tell you is that wanting to spend time with your husband is completely reasonable. The fact he is leaving you alone when you are 9 months pregnant is pretty cold in my eyes. I honestly wish you the best and I wish you a speedy and painless delivery!