My Thanksgiving/Christmas Eve Dilemma–Please Help Me! [POLL]

I'm having a MAJOR dilemma now that I'm engaged. It applies to Thanksgiving, but my real problem is going to be Christmas Eve.

My family has long celebrated the holidays on Christmas Eve. It's pretty much the only time we get together anymore. Once I met my fiance, I soon realized that his family also celebrates Christmas Eve as well. It's their yearly tradition. Both families would be pretty upset if we favored one over the other. The same thing applies for Thanksgiving.

Now that we're kind of going to be tied together for the rest of our lives, we want to spend the holidays with each other.

The problem is simple really, it's the answer which is not so easy. How do we go about this? What do we do to make everyone happy? Is it even possible? Help me--I can't be the only person who has ever gone through this!