The man he is now is awfully angry. And verbally abusive. And on the edge of physically abusive. He could certainly change, but of course there is no certainty.
With all of his anger towards you, and the way everything is your fault, I am wondering if a separation might be a step forward. I am thinking that as long as he is living with you he has no reason to look at himself as a source of his troubles. Because it is all obviously your fault. Of course, at least at first, he'd probably still blame everything on you, but at least you wouldn't have to hear it.
Here's a real 180.... what if you started a conversation with him, and calmly brought up separation, and said you'd like to work out a plan with him, so that the two of you can tell the kids. Catch him when he isn't already wound up (if that's possible) and maybe you could have a rational conversation. Otherwise, I'm afraid he is going to make a unilateral plan, and blurt it out to the kids at the worst possible time. IF you bring it up, it might disarm him, a little.
I don't know what direction things would go after that, but I am not convinced that it would have to be downhill. Sometime you have to back up a bit before you can go forward.
