I did have a therapist advise to err on the side of caution in coparenting. It can give children a sense of inner hope for reconciliation. I am positive my sons are well beyond the holding out of hope and desire.
Holidays are kind of a jumbled oddity. When the boys were little, there were a couple of Christmas mornings when he came over to see their faces light up. Typically, however, he works many holidays as he did even when we were married. There have been years the boys have visited and celebrated with him on the Eve then I'd pick them up for the night into the next day. Some Thanksgivings we'd plate up some leftovers and bring him food to his workplace by virtue of the boys didn't want their father without a hot plate of an important meal.
I get how difficult it is to force kids to choose between family homes and whom to spend holidays with. I also appreciate the shared heartache of some of my friends who by decree must be separated for weeks at a time.
Coparenting is also a matter of compromise. Kids can be resilient and understanding of celebrating on different days.
I've seen various scenarios and agreements between amicable parties.
Where do things go once the kids are fully grown and on their own?