This. ^ To be honest, I can't think of anything worse than having someone else's family Christmas forced on me. I'd rather just be alone. Yes to popping to the Church for a few services during December, and a few Christmas-lights switch ons, and meet up with 3 or 4 friends for a coffee or pub lunch, and a few extended family visits to swap gifts (during the first 3 weeks of December,) ...
But NO to being at someone else's house/home/family Christmas, on Christmas Day... No thanks. Not for me. Not even my own adult DC. Go and visit Christmas Eve, or the 23rd, and drop gifts off, but it's home all day on Christmas day.
Me and DH spend it alone after seeing our DC/partner/their parents during the middle of December. (DC Christmas Eve or 23rd..) Around 3-4 years ago, DC asked us to go to the town they live in, (25 miles away,) and go for Christmas dinner with them and a bunch of extended family of their partner, and a bunch of mutual friends of them all. Would have been 30 or so people excluding us. (At a restaurant near them.) All meeting at midday, Christmas dinner at 3.30pm, and finishing around 7pm.
Would have cost £60 each not including drinks, and the price of a taxi if we had wanted a drink (which we would.) Probably £100 return on Christmas day. It was all right for the rest of them, because they all live within 2-3 miles of one another. They also all pretty much knew one another. We'd have felt out of place.
DC was just being kind, and thought me and DH would be lonely and 'left out' not being included. They couldn't be more wrong. We LOVE Christmas Day alone. We've had too many Christmasses of people-pleasing and having a dozen people around, or having to visit a dozen people, and have no Christmas to ourselves.
Like the OP, our DC seemed to want to foist their big Christmas with 30 people on us. We politely declined a couple of times, and they didn't ask again. They just don't get it, that we neither want or NEED two dozen people we barely know around us at Christmas!!!
@Ifeelabitweird YABU. Let your DP have his Christmas day to himself and stop forcing YOUR family on him. You have only been together 2 years. That's nothing!