Help, do i need to leave?

My SOs been really stressed the past few weeks, were financially struggling, because hes paying for his debts to get good credits again. Yesterday he was drinking, not drunk, everytime he drinks, he gets evil. He kept ranting about one of his enemy to me. While my 1yr old is super clingy and whiny to me. My SO got mad at him for whining, and spanked him on his face, hard. I got angry, and yelled at him. He yelled back. He started saying, "man, yall dont know anything about my stress. Yall always make me not get any sleep." But the kids always go bed at 830. He couldve gone bed at 9pm, but chose to stay up to rant about shit til 12am. He does this all the time when hes about to go work. But hes blaming it on the kids and i that he never get any sleep whenhe has work. I said this to him and he said its because of us thats why he chose to stay up to talk and couldnt stop talking. He said im unsupportive to him cause i dont get the kids to bed early, so he could go bed. Bitch. He then said that were so annoying, someday hes just going to kill all of us. He said fuck all of us. Hes sacrificing for us, hes working hard for us, we all need to shut our fucking face, and stop pissing him off. Stop annoying him. He said he might lose his job because ppl are getting laid off. That if he lose his job, we will all die of hunger. He said someday hes going to run away from us and go start over. Everything and everyone of us is so stupid. Fuck all of us. He warn me not to annoy or piss him off at this time cause hes super stress and its draining him mentally. We never did anything wrong to him! And kids will be kids! Do i leave and let him deal w his problems himself? Or i stay and help him through it? I understand hes stressed and all, but it isnt right for him to take it on us.