The legal side is very tricky here - I have a close friend who had a similar situation - despite his wife crashing her car drunk, beating him, etc, etc ...... she got the house and kids! He had to see his kids get raised by her drunk.....until it killed her 10 years later.
My wife - on the surface - seems an ideal mum. A load of empty tins and a few stories of her throwing up wont get me the kids in a legal battle.