You sound so dismissive of him being far away from his family - and I hate the attitude of 'well if you choose to live abroad, those are the consequences'. It shows such a lack of empathy.
I've lived abroad for 24 years now; I originally didn't mean to stay so long (and it's been more than one country) but life moves in mysterious ways, and what with work and then love, and now children/teens at school, I'm not about to pack up and move back.
But I don't see why that should mean that we always default to being here at Christmas, or at any other time, and we don't. Sometimes I go by myself (not at Christmas, but it's never been necessary), more often we all go together, but we always talk everything through. There's no way dh would just "say no" to a suggestion from me - if he thinks it doesn't work, we discuss it until we agree on a solution, whatever that may be.
I also have an at times slightly fractious relationship with my parents and siblings. Nonetheless, it's been really hard with covid, and not seeing my parents for the usual 1-2 times a year, particularly as they're elderly and my father's not well, has been awful - I feel sad and guilty; they miss out on so much of their grandchildren's lives, and it makes them sad, of course it does.
You don't need to have a super close relationship to your parents to miss them, or to want them to be a part of your family's life and traditions, or to understand that they would like a relationship with their grandchildren, even if it's sporadic.
My MIL has stayed regularly with us over the years, and I'm fond of her, but when she asks how my parents are and I say it's hard, it's been such a long time, they never see the children - she immediately counters well, what can you do, you live here, you can't move back. I have no intention of moving back to the UK but her fear of us doing that - and therefore putting her in the position my parents have been in for 24 years - is all she can think about. It really grinds my gears - there's never any sympathy or understanding, it's always - you live here, tough luck.
I incidentally didn't speak the language when I moved here, but now I'm fluent and my children are bilingual. My SIL still makes comments when she's talking - she'll suddenly pause and look at me and say "Do you actually understand what I'm saying?"
There are lots of little things that make it hard to live away from home and in someone else's culture and someone else's family, no matter how happy you are overall with it, and I really appreciate it when dh or anyone else is sensitive to that now and then.
I don't know what else is going on in your marriage, but on this topic I have to say I agree with what a few of the other posters have said. How important are those "holiday plans" you'd made? Could you try and see it from his point of view and be the bigger person? You do sound a little controlling and if I had any sense that my dh would veto visits to my parents, I'd feel trapped and helpless.
If generally you rub along well together, I don't think this is worth blowing up your marriage over, if only for the sake of your children. I think your dh is trying to communicate something to you, albeit not very adroitly.