BTW,when I said don't be H's judge, I didn't mean don't judge H. I meant don't pronounce your judgements on H, keep them to yourself. (But, if you want to work on not judging H, that sounds good too.) Psychoanalyze him all you want too, just keep your theories about his problems to yourself. (But, you've also probably figured out the more you can quit trying to explain his psyche to yourself, when even he doesn't understand it, the better for YOU.)
"I do plan on asking the judge about it, citing the poor parenting of her own children and lack of moral character."
Hey, doesn't hurt to ask. And, maybe the judge will do something in your case, especially in light of CW's D's cutting. (But, don't count on it.) If they won't grant no contact, maybe they will at least say that she can't be alone with the kids. (But, don't count on that either.) If they turn down both requests, this leaves fighting for full custody. I doubt you believe that is in the kids' interest.
Anyway, I don't think the struggle with H will get you anywhere other than to a place where there is increased animosity between you and H that bleeds onto the kids. Better to either get a court order regarding the CW sitch and handle any violations in a businesslike manner or let it go.
You are trying to control H's actions through your own. But, your approval/disapproval is not going to determine what H does. H will expose the kids to CW precisely when, where, how he wants to. If you fight him, he'll feel good about doing it as a big FU to Donna. If you endorse it, he'll feel good about doing it as something OK with Donna. If you ignore it, he'll feel good about doing it as something that doesn't matter to you. Blah blah blah. He will rationalize and justify whatever he wants to do no matter what you do. Not in your control.
As for telling the kids about the A and the details, sounds like a great idea to get a professional opinion. And, remember, with kids, there is a difference between lying and keeping adult matters private. Maybe, "Kids, you might hear in school that CW and Daddy are dating. Yes, that is true. Mommy and Daddy had some adult problems and we aren't together now. CW and Daddy are dating."
I doubt that the kids will push for more details.
Like I said on BFM's thread, think of how you would want to protect the kids R with their Dad from all this crap if he came home today and you two built a wonderful M together. Your kids deserve to have that R with their father protected whether or not you reconcile.