I know IABU (probably)
I have DC 80% of the time, all the mundane everyday stuff is my responsibility. He has them 2 nights a week no full days. He's already been on holiday for 8 weeks in total this year. I don't think it's fair that everyday life gets shared 80/20 but when birthdays or Xmas rolls around he wants 50/50.
It's usually shared Xmas eve -10am Xmas morning/10am Xmas morning - Boxing Day.
It's his turn for Xmas eve this year. Xmas eve is our favourite Xmas time (much more than Xmas day) and I really really don't want to had them over.
AIBU aren't i?