Staying in a hurtful relationship isn't good for the kids. If you are having to yell at him, deserved or not that's something the kids will be better off without in their house. And if he wants to remain a dad after separating he will have to take a much bigger role in their lives even if he only has them weekends, since you won't be there to help him out. So it may be worth putting the reality of that to him before you make your final decision. It's a huge decision and you should both have the chance to think carefully about the consequences of making it. I do believe from your description of what is going on something does have to change though, the situation as it is is just destructive to all of you.
I have been in his situation before, though I would say my situation was different it may not have been very different. My hindsight would tell him to leave that job now and start repairing the damage it's done. Even hindsight doesn't pay the bills though so whatever you both decide it will probably be a difficult road ahead.
I wish you the best. You can email me through the link on the top of this post if you like.