Its going to suck though. This will be the first Thanksgiving without my family since we got married. And my first, ever in my life, that I don't really have a family to share it with. At least I'll be making my time useful to others.
Personally, I think you made the right decision, and I admire the way you have chosen to spend the day.
It will be better to give up this one holiday if it will influence positively in how the future ones will be spent. I am a strong believer in stepping back from the WAW. Don't be scared to let her have the experience without you.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!