Back story is that we always have a big celebratory lunch at home. Huge tree, home-made Xmas pudding (which we all cook together weeks before), grandly decorated room, best china, crystal and silverware, etc, etc.
And always - for every Xmas of my kids' lives, my aged parents (I am an only child) and childless aunt and uncle at lunch with us. Then we would go to his parents' for Xmas dinner.
And now stbx has announced that the kids are to come with him to his uncle's place for lunch. And he has put me in the position of having to say Yay or Nay.
How do i cope with this one?
It seems pretty obvious to me, what the kids do NOT need right now is a break in tradition. They've got enough to deal with as it is. So continue on with your traditional lunch with or without H (but definitely without OW) then he can take them to his parents' house for dinner.