I'm also wondering when my darling W is going to tell our daughters she's actually divorcing me. She hasn't said anything to them. They still have hope.
If you are sure it is going to happen then tell your W that it needs to be told to the kids. Set up an appointment with your W to do it together. Your kids need to know so that they can process the info.
"You can't stop the waves, but you can learn to surf." Jon Kabat-Zinn
