First time reader to your threads, im very sorry that your situation has turned like this. But in all honesty, you know now don't you. Its a sad relief to finally know the truth in a way.
Your not second guessing yourself, you no longer have to mind read or project. You have the answer. Now you just need to figure out what you want to do with the information. I would certainly take my time thinking it over.
I think what your husband is doing with the "You threw me out" is very script like, before he could profess his innocence and make you feel guilty. Since the truth is now out, they need to reverse it again and make you out as the "bad" person for splitting up the marriage. I know, its crazy, but they don't think rationally. Believe none of what they say, and half of what they do.
Going dim is totally for you as a way of keeping yourself out of the guilt game. Maybe you need to take a week or two, think things out for yourself. He'll try to drag you back in, to justify what he's doing. The more he can throw blame towards you, the more he thinks he's letting himself off the hook, and that what he's doing is the right decision. Its time you set some boundaries for yourself, and STICK to them, before you drive yourself insane.
Detaching is so under-rated. I know its hard, but you have to separate the emotional from the physical. Treat this like a business transaction. When in doubt in a situation, ask yourself "Is what im about to do or say really going to help the situation". If the answer is no, then don't get wrapped up in it. Don't let yourself to continue to getting dragged into the guilt, anger, betrayal. Act "as if" your moving on, its time, drop the rope a little, and let him play with his own demons.
I would almost handle it like a legal separation. Schedule him wed. and every other weekend with the kids. Keep contact to email only. Make him put in some work, you've been carrying the torch by yourself for too long. Since he's already convinced himself that he's done, separated, then let him live with that decision for a while. It works two fold, he gets to see what life is like without his family, no to be mean by you, but the reality of his actions/choices. And 2nd, push him towards the fantasy life that he thinks he's going to be living, he might just find out its not what he really wants. He needs to find that out for himself.
The sex must stop, imho, your losing some self respect, you don't know what or who he's doing things with. Don't risk catching something cause you need that emotional bond right now. He might even over the next couple weeks attempt to "recapture" you in a way, but you cant allow that until your sure he's actually committed to trying. Your a doormat otherwise.
I might be totally off base here, but you need to start being proactive for yourself, not reactive in hopes of what your doing might work, it wont. He needs to make that journey all by himself.