God, that breaks my heart. I hate hearing stories like that. It's happened in my mom's family. Everyone was raised the same but over the years, for whatever reason, whether someone criticized the other, or when my uncles sold my nana's house and belongings without consulting the sisters, who knows? Some siblings didn't talk for years. I have 3 girl cousins I rarely see, except at funerals. That's so ugly. Only the middle one, my age, has been calling me, especially since her mom died a year before mine, and she expressed horror and asked forgiveness that her mother wouldn't let her contact me, we don;t know why. It took my mom's death for all the cousins to finally call me and keep in contact. We have 30 years to catch up on. My mom became the matriarch and finally, years ago, contacted every sibling and made each of them call each other etc. I find it so hard to understand. My best friend's family is so wonderful and close with 5 kids, all cousins, grandchildren are close. I'm so jealous (in a nice way). My brother, who lives with me. basically lives a life of his own. I don't hate him, I just learned to accept that I'll never ever change him.
Kim, just my opinion, but it's the holidays and I think you and hubby should go. If you stay away, you're giving in, and they'll relish it. If they start anything, just be sweet and tell them you're there to enjoy yourselves, not to argue and walk away. I'm the kind of person who would purposely show up to display my dignity and grace under fire. If worse comes to worse, you graciously say an early goodnight and let them look like the *b's* that they are. I hope you and hubby go.