I know you don't want this. Trust me I get that. In detachment, it will get worse before it gets better - sorry that's just the way it's going to work. If you read my thread, I thought I was at a great place being detached but I had a freakout last weekend. I posted it here. But, then I came out of it and felt much stronger and better.
There's tons of stuff on how to talk to your kids depending on their age on this forum. Yeah it kills to see them go through this - i still don't think it's fair on them and that they deserve this. W shattered everything for her own selfish gain and didn't even give me an inch. I gave her every possible option to work things out and she flatly refused - for which I will only forgive her if she ever shows true remorse. She is putting all of us through this because she couldn't handle her $hit and took the cowardly way out IMHO - but I can't do anything about that and it is completely out of my control.
The best I can do right now for my kids is being present with them and doing everything possible with them to make sure they feel they are secure and don't feel neglected or abandoned. It is hard because kids will show their emotions and ask questions. I can only counter it with love showing them immense amount of affection.
My D tells me she misses her mom and when she's with her that she misses me. It truly breaks my heart and the only thing that I will have a hard time forgiving my W for. I am an adult and I can get through whatever crazy she throws at me.
Just tell your kids whatever is age appropriate for them and don't paint your W as the villain. She's still their mom and no matter what, they will love her.
I am sorry your D is going through this. I know how it feels.