OP here with comments and updates....tried to log on last night but the server was down?!?
First, the update: My dad called me yesterday and he was definitely a bit down. Apparently, Lita's kids decided that they are leaving town early (tonight instead of Sunday) so Lita has to be there at her house the entire time until they leave and my dad is home alone. Not sure if this is a bad sign for the relationship
Thanks for all the comments. I tried not to post a lot of details because obviously I'm extremely biased and I feel strongly that Lita should have showed up at our Christmas day meal. DH is on the other side and agrees with a lot of you who said that it was unreasonable to expect her to leave her family on Christmas.
My dad and Lita present themselves as a social unit IMO even though they are not married. Lita basically lives ay my dad's house. She is present at all our family celebrations, birthdays, Easter, Thanksgiving, etc. with my dad. Thanksgiving was at my dad's this year, Lita and I cooked everything.
2 of her sons were there at my dad's as well.
With all her family traveling to her this year, it became obvious that it would be hard to host everyone in both families. In Lita's family, they have a tradition of a big meal/presents on Christmas eve, with a more low key Christmas day. So it was decided that my dad and Lita would celebrate with the big traditional dinner at her house with her family on Christmas Eve, and then my dad and Lita would celebrate Christmas with our family Christmas day. I will admit that I don't know if this was my dad's idea or Lita's, but clearly both were in agreement.
My dad opted for the easiest plan--hosting at my grandmother's. Since my grandmother cannot drive, someone would have to pick her up/drive her home. She also is quite forgetful and really couldn't cook an elaborate meal. Hosting at her home meant that all we had to do was bring the food and clean up. I suggested ordering a pre-cooked meal (turkey or ham) from a local restaurant but Lita wanted Chinese takeout for some reason. My dad also liked this idea. I have nothing against Chinese food normally, but I am a definite SS here--I really enjoy the traditional dishes and Chinese food doesn't seem like Christmas to me. I will also admit there was a bit of jealousy--my dad and Lita got to enjoy a big traditional dinner on Christmas Eve so of course they didn't care that they didn't have it for Christmas day.
Unfortunately, when Lita informed my dad that she wasn't coming, the Chinese food order had already been placed. I suppose I could have called around and figured out something else, but we were all so busy with last minute preparations that is was easier to just go ahead with the plans.
Lastly, I wanted to comment about seeing family over the holidays. I love my family dearly and I live close enough( 1 hour by car) that I can see them often. But even when I lived farther away, when I came home for the holidays, I never expected that I would have my parent's undivided attention for a week straight. They would often be invited to holiday parties, etc, that I was not invited to. I was fine with that.
Lita herself even made the point that Christmas Eve was the big day for her family, which she had. I just can't help feeling like our family was good enough for Lita when her family wasn't around, but the minute her family came we were no longer needed and any plans could be discarded.
I told DH next year, we're going to Hawaii by ourselves.