I am sad about the future when for the rest of my life and the life of my kids and my grandkids, holidays are going to get split up. It makes me very angry and resentful.
This sounds like catastrophizing. It assumes you’re never able to let go of your anger enough to spend a holiday together. 11yrs after my D, my XW and I get along well. We’ve shared a few strategic holidays since year 5. It also assumes when your kids grow-up if you’re still angry they will humor you and not just say, “Thanksgiving is at my house and everyone’s invited.” I had an XGF who did that.