Hope, I'm sorry for your situation, and the obvious distress it must be causing. The walking on eggshells part alone would keep you in a high state of tension, and this can't be good for the children. Is counselling and him seeking treatment out of the question? Kicking Mom out? Can you talk to him when he's sober and tell him how he's harming the marriage and children? If none of this is possible, or doable:
Make a list. 1. Find legal advice, especially about the custody side. 2. Think about finances; what can you put aside? who will help you? 3. Document as you have been doing, record if you can (check with lawyer). 4. Put together an emergency kit if you have to leave in a hurry. I'm sure there's more, but taking small steps will help you unfreeze yourself and give you momentum.
A couple of points: if you can prove he drinks excessively, and is belligerent, bullying, threatening etc, no court is going to buy that it's your fault. Assuming you're a good regular mother the the kids will obviously be safer with you. Also, if you are afraid, intimidated, bullied, call the Domestic Violence number and talk to them. You don't have to be battered to qualify, as DV comes in many guises.
Stay around this forum and you'll get a lot of support from people who have been in your shoes.