What should I do if I think my marriage is falling apart?

[Nugget]

My husband and i have been married almost 5 years. I take care of his 3 children from a previous marriage because they don't live with or see their mother. We also have 2 children together. I work full time to support him and the kids so that he can go to school. For the past year or so he's been very hateful. We're a christian family, and he cusses and yells and me and the kids all the time, even our 1 year old gets screamed at. Whenever I ask him for help around the house he only gets mad and says that he does more cleaning than I do(which isn't even nearly true) and that he won't help me. I can ask him to do one thing, like give our kids a bath, and 8 hours later, he still hasn't done it. when i ask him about it, he just says "if you're gonna be a b*tch, then i'm leaving", and goes to the next room. that's just a general example. i don't want to divorce, but i can't take all of the verbal and emotional abuse much longer. what should I do to save my marriage?