What outcome do you want OP?
The biggest obstacle many people face is wanting to change the actions of another person without changing their own status quo.
You are still at the point where you think you can fix him, and I understand why that feels like the most straightforward option.
If he dealt with work stress in another way, if he didn't get so drunk, life at home would be much better for all of you. You feel right now that if he did that, you wouldn't have to have a protracted and complicated separation, the children and you don't have to have their lives dramatically altered and disrupted.
He has a drink problem. And he's no different from all the other people with a drink problem. His stresses aren't unique to him. And the fallout is not unique to your family either.
You are about to learn that you didn't cause it, you can't control it and you can't cure it. Right now you are washing sheets and thinking a telling off from your marriage therapist will improve matters.
I think you've a ways to go yet before you realise that you can't change another person. Sometimes they can't even change their behaviour even though they want to. And when you realise that you can't live like this any more, when you are exhausted at the chaos his drinking brings, and you've no option but to walk away maybe Mumsnet might be more practical use to you then.
For now, the only advice I think you are able for is that you should probably just get waterproof sheets and cheap bedding and only swap over to your nice bedding on that bed just before someone comes to stay so that when he does have a bender, you are minimising the impact to your household budget. As long as he thinks he's got every right to piss in his bed at home, and that your job is to clean it up after him without daring to hold him to account, that's all you can do really, isn't it?
The best of luck to you and your kids 