I feel your pain about your kids. I too suffered divorce M married OM. F lost in trying to rebuild his life. I am terrified of that for my S. He idolizes his father. Has since he was a little boy. I see the pain in his eyes, the concern he has for me and the confusion he has right now trying to understand why his father is doing all of this. I can't explain it to him. I don't understand it myself. I just feel like they get into such a selfish rut....
I too cannot "go dark". We still live in the same house. We still are devoted parents. (So far). I understand what you are struggling with.
Good luck.
If you focus on the past, you ruin the future. You can only live for today.