First off, I just want to say I empathize so much with you. I've totally been there. I know how you feel and it is awful. I wanted to share a few thoughts with you:
-- Steve85 also alerted me to the possibility of a PA. I thought there was no way it was a PA. I was totally wrong. I was glad I was prepared for it and recommend you do the same.
-- My H also did the whole rewriting of history, I was this control freak who had completely dictated every aspect of our entire adult lives. BS. For me, stopping caring that he thought that and being firm in knowing what I knew to be true helped.
-- I don't know that you need to share things about how your kids are feeling with him right now. It doesn't sound like he has the capacity to listen to it without coloring with motive from you. Can you focus on just being there for your kids without needing to count on him? Maybe before you decide to bring it up, think through the possible/likely outcomes. If you think there is a good chance that the outcome will actually be something beneficial for the kids, I'd do it. Otherwise, I'd put that energy into yourself and your children. I agree with Alison about sticking to the facts only.
-- Detaching is So. Hard. It used to drive me crazy reading all the vets saying just detach! Like it was actually possible. It seemed so far away from me, like to the level of attaining true enlightenment. But, if you keep working at it, it does come. This might be a fake it til you make it kind of thing. The other two things I'd recommend would be to really focus on yourself and get to know your own feelings and moods, so that you can start to invest more time in what helps YOU. What helped me was yoga, self-care, and the mantra over and over that I control myself, nothing else. But you should find what works for you. Also, taking time to explore what D might look like to take the fear associated with it away.
-- My H also told me I was no longer in control, that I wasn't in the driver's seat on this. True. But I was able to set certain boundaries that I stuck to (even though slightly different than those of others)-- basically that if we split up we would not be friends, and that I refused to work on our R with a third party in the mix. She had to go. He really struggled with this, wanted this fantasy D where we'd stay best friends and he'd live next door with AP. I was really clear and consistent that that would never, ever happen. I wonder how friendly you are to him in the day to day?
Hang in there. You got this. I know it is awful but you have a great resource here for you!
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing