MCE - I am sorry you feel a need to defend yourself.
Many of us had exact same fears - your story is not unique at all. Leaving an addict I loved is the hardest thing I have done, it is not the walk in the park.
You have your own income. Insurance thing can be figured out - and expenses can be reduced. You are leaving with a person that physically abuses you, endangers kids, and is a financial liability waiting to happen. You have grandparents living nearby - one of them is sober right? They could come over and assist with childcare while you are at the al-anon meeting. I don't go to meetings for that very reason - and I don't have family around - so I understand.
I agree with the posters above there are always options. They are all requiring changes, downsizing, tightening up budgets, moving, and various levels of heartbreak. Continuing as is is not an option.
You don't have to move out of your house, she does. Call the police next time she assaults you. Call the police when she drives drunk. She could kill someone on the road.
This is America for Pete's sake, as long as you are sober and mentally intact yourself, your kids won't starve. There is enough food, kind people and material goods around. Community is more helpful than you think. Being married to an addict is extremely isolating. Trust me - my fear kept me going back to the addict and hoping for the best, but at the end I broke free and ended up much better.
Nothing changes if nothing changes. If there is a will there is a way. Your 17 year old is strong and brave, and deserves better than living with alchy grandpa. Your 3 year old has no choice, you do. Please get your children out of this crazy environment.