This will be the 3rd Christmas Eve I have not been in the house with DS. He wants to stay in "his bed" in "his house" on Christmas Eve. I've always supported that and not got involved as my ex enjoys doing all the special stuff in the evening and I've never been wanted in the evening.
We do spend Christmas together and share a meal. But it's crap missing out on the evening and the excitement of the wake up in the morning.
I've now got my own house and DS does have his own room. He stays twice a week. But his mum's house is still home.
I do understand why he wants to stay with my ex. Think he's a bit worried about Santa (he's 7). It's still very very hard not being there.