Family boundaries

I am establishing boundaries with my extended family (parents, grandparents, aunts, cousins). It has to do with ongoing family celebrations. I don’t want to meet every weekend for some sort of celebration. I want to do my own thing and meet once a month. I don’t enjoy declining their invitations and don’t want to show up annoyed and missed out on a low key weekend.
current thought
C: Family gatherings
T: We meet too often
F: Annoyed, irritated and controlled
A: tell them how annoyed I am about the celebration number 100
R: guilt

New thought:
T: I can attend as many or as few celebrations as I see fit
F: Freedom
A: Show up at gatherings happy to see everyone
R: Less complaining, less guilt

So for relatives confronting my declining, do I say that I can’t come? They always ask why and never find my reason enough.