Hi 22Red and Welcome to SR
What a terrible thing to be going through, I cant imagine quite how you must be feeling. I have only recently too woken up to the fact that my marital problems were largely due the my husbands alcoholism and I know how devastated I felt and I wasnt pregnant.
I like you, have a good marriage when my AH is sober and this is what has kept me from leaving when times have been difficult, so I have stuck it out for over 22 years, bringing up children etc. I too have spent so much time sleeping on the sofa its not funny and a few years ago we bought a pull out sofa bed and it has been a blessing.
Thats by the by for now, but I just wanted to say that to be honest, I think that you have enough to deal with right now. Your husbands problems can wait and will still be there once the baby comes and you should really have a clear head when you start to deal with those issues but when you are ready, mentally and emotionally. In the meantime, just try to concentrate on yourself and your baby and mother nature will give you a helping hand with that one.
Once life kicks in and the euphoria of having another newborn baby to look after has subsided, then please pick up where you left off, start to read what you can about the disease of alcoholism, come back and visit us when you can.
Good luck with your birth x