MIL comes to us every Sunday for lunch - staying about 5-6 hours (less in the winter as she doesn't like driving in the dark). We no longer invite her, she just assumes and comes. If we cancel, she comes on a Monday instead - she self invites saying I'll come on Monday instead. DP has Mondays off - it was meant for us to be able to spend more time together, play tennis that sort of thing. I like her very much even though she is sometimes imperious and demanding. But I do get a bit cross about her coming every Sunday especially as she stays so long. It is the only day off we have as a family as my big sons play school sport on Saturdays.
She is not my two big sons' grandmother. She can't help but make a fuss of the little ones (her grandchildren) and this makes me feel bad for my big sons although I don't think they notice in all fairness. I just think it would be nicer if she wasn't ever present on our only day off as a whole family.
I've mentioned this to DP a few times (let's say 4 times over the past 6 months) but he buries his head in the sand.
What would be a good compromise and AIBU?