I'm so sorry you are hurting. It's natural to have experienced hope again after the changes and conversations with your H over the past few months. Give yourself space to feel your feelings and don't beat yourself up.
I do agree that accepting the D and going forward with it is your best/only option. Working towards completely separating your life with D4 from his life with D4 is probably a good thing to focus on now. You and she are a family, he and she are a family, but you all three are not a family anymore.
With regards to cutting out family time... You could approach it by wanting set some co-parenting boundaries and ask for his input? "This how I'm picturing things being once we are divorced. XYZ. What do you think? I'd love to implement these changes straight away to prepare D4 for the divorce." You could frame it as being for D4's benefit to avoid causing confusion about her family structure and to explain things to her going forward.
The idea being that demonstrating calm, logical cooperation will prevent you coming across cold and angry. What do you reckon?
