If your H is anything like mine, as soon as he walked out the door he considered us not married anymore. My H even went as far as to say he never cheated on me physically until the day he left and moved in with ow. Like it was OK then because he had left.
My H at first was clearheaded at work, but lately it has been mentioned to my S26 (who works at the same place)that his dad has been acting strange as far as memory lapses, etc. The stress seems to be affecting him.
Go dark on him. It's harder with kids, but do it as much as you can. Let him see what he is missing. If you don't want a D, let him handle it. Use this time to figure out what you want. Take your own journey, focus and work on you. Try to detach from your H's drama as much as possible. You can't fix this for your H. It has to be his work from the inside out. Patience is the key for you.
