OK, so a bit of background...
My parents split when I was 16 and my Dad met someone about 4 years later and they've been happily together and married for about 20 years.
Since I moved out to go to uni I've never been invited 'home' for Christmas day. My Dad's excuse is that they always go to his wife's Mums for Christmas which is fair enough. I have said in the past that I'd really like to have a Christmas day with my Dad and if he ever was at home on the day it would be great to get together. I've offered to help etc.
Anyway, I called him last night and tried to make arrangements to see him over the Christmas period (not mentioning Christmas day as I assumed they would be going to his MIL's as usual). Anyway, he casually mentioned that they were having his wife's whole family over for Christmas (9 in total, including their niece). No mention or invitation to me or his Grandchild (who he hasn't see for months).
I just feel quite upset about it tbh, that he hasn't even considered his 'old' family at all, despite me asking about it in the past. Before anyone says that I should invite him to my house, I already have in the past and he's refused saying he's going to his MIL's.
AIBU to feel upset and what do I have to do to spend Christmas day with my Dad?