to not invite my sister for Christmas?

You sound like an absolute cow and I hope one day your children take a leaf from your cook and exclude you at Christmas to focus on their own little families.

Still waiting for the reason why you dislike your sister so much you want her to spend her first Christmas without her mum on her own.

Are you just generally averse to people you didn't grow yourself?

So if she hadn't stepped up would you have had your mum round or would you have left her to be on her own? Seems your sister was the one who facilitated your own little "family" Christmas for the last 5 years.

Anyway, you've clearly decided on not inviting her.

You aren’t the slightest bit confused … you know exactly what you are doing - which seems to be some huge wind-up, on the topic of “boundaries”

Well, there’s a word, and it’s called family. And in theory, your sister is your family. And in the absence of any other family - yes, she probably considers you & your children her only family.

Here’s the thing. What you’re planning for Christmas is mean spirited towards your sister. In fact, I get the impression you don’t particularly like her. It seems you’ve already made up your mind and have come on here for validation which you’re not getting - because it’s really cold hearted and mean to knowingly leave her alone (this of all years). And to put it down to her choosing not to have kids - how long are you going to hold that against her for? It’s not even relevant to the situation. But if it makes you feel better then sure, blame her childlessness instead of your selfishness.

But you said you "wouldn't let" your dc spend Christmas with a partner and that they knew what your "expectations" were. That attitude contradicts your apparent selfless hopes for their future Christmases.

It’s definitely tricky when you’re expected to host other people year after year, I do understand that

I’d follow @Nestingbirds advice this year though and make it as simple as possible. And don’t mention 200-mile round trip lifts, that expectation is ridiculous.

Your sister thought she would have her husband too, things change.

Sounds like you've made your mind up.
You came here for affirmation because derp down you know you're not doing the right thing.
Self-care is not inviting an overbearing MIL and her drunk partner who spends all day criticising your food and home. It's not excluding a sister who has just carried the burden of care for the family.

But you do you... I hope your sister has some nicer friends.

There is every chance you will be on your own op in later years. Dc grow up and have their own families and in laws etc. Your dh is not guaranteed a long and aged life.

That’s not the point though. Your total lack of empathy is the issue here. Your poor sister.

So what exactly is your “AIBU” OP? You clearly already think you are being reasonable .,

Did your sister spend the last 5 or 6 Christmases with your mum? Seems you abandoned your mum for your "family", lets hope your kids don't follow suit.

Why would you expect your children to spend Xmas with you once they have their own family. Surely your whole view point is Xmas is for the nuclear family so you won't be accepting any invite from them or expecting them to come to you

Well if they choose to prioritise their immediate, family rather than extended family you might.

Its amazing what children learn from their parents.

You resented your own parents spending Christmas with you and wish you had objected. What if they all do what you wanted to?

Ask your sister to bring the starters snd cheese ( prepared) you do the main course. Teens are in charge of dessert. Dh cleans and tidies everything up whilst you and ds put your feet up and toast your mum.

I wouldn’t leave her on her own esp not this year, no.

With a Sister and 3 nieces / nephews, maybe your DS thought this too once upon a time. And yet, here she is.