Ditto Lizbeth, big time.
"Managed" relationships aren't really relationships, but tense transactions.
I think your daughter was right.
She knows there's no mythical daddy hiding there.
Let them find their own way to whatever they want, or don't, with him.
It IS something to grieve, the loss of the family dream.
But no point in an endless funeral.
Enjoy the holidays in your own way, create new reasons to be happy and ways of sharing.
That will be better than the obligatory bio-family stuff. If it's broken, it's broken. But you can create wholeness on your own with your kids...that will model something healthier for them.
Norman Rockwell haunts us all, but we can paint too.
Wishing you peace,
Hopalong