I second so much of all of the prior posts. Literally everything Allison said was gold. I think the biggest point there is you have to let him figure all of this out on his own. All of it. Not piecemeal. His feelings. His plans going forward. All of it.
Steve's post was gold too. You have time here. You are seeing the situation for what it is. But don't rush this because you're in pain. Slow down if you need to. Do nothing for a minute. I know we do so we have some control, but you don't have to do that. You can honestly sit back relax and watch him tire himself out like a toddler or a puppy and take action when you're more than good and ready. And you know it's not a knee jerk reaction to his stupidity.
FS has a lot of good stuff there for you about protecting and taking care of yourself and how being non-reactionary even if you can't detach is such a good way to do that.
Honestly the only thing in the prior posts I'd be iffy about is the kid stuff. H is still firmly planted in your bed and terrified to move in either direction. Just let it be. And if that time comes, deal with it then. you don't need to rush this any more than you do a D or kicking H out. Take your time here. I do think he should be the one to tell the kids. But while you're girls aren't babies they aren't as old as mine either and I don't know how appropriate it is to dump the A on them. I think something like this needs to be an age and situation appropriate information trickle. Forcing WS/WAS to traumatize their children to me has always felt super manipulative. But that's just me. I told H that he needed to explain to the girls why he was on the couch, and I didn't care what he said but I needed to know how much he was or wasn't telling them that I'd get on board because one of my priorities was doing what I could to preserve his relationship with both of them to the best of my ability. (Shouldn't have done that in retrospect since he got so caught up he had forgotten our kids at school more than once to be with OW among other things he did to just collapse those relationships) I stand by not traumatizing them unnecessarily though. And be there for the conversation. I also opted out of that. And that was a mistake. Less so with D17 she was very clear about how she was feeling about what was going on and was able to steer the conversation. But with D16 he pulled this "don't you just want me to be happy?" BS, and the only push back she was able to give was "but what if the rest of us were happy the way things were?" Which then led him down a path of well I'm not happy so I'm making WF unhappy, and if I don't leave we'll all be unhappy soon. Your H is so delusional right now, I don't want him to say something super inappropriate or unhealthy or insane to your kiddos with out you being there to guide the conversation or shut it down entirely.
You're doing so well my dear. Stay strong. Stay focused. Take care of you.