Family can suck. I have cut off all contact with my mother. She has not been a part of our lives for almost 4 years. She was abusive to me in every way, except sexually,when I was a kid. I had thought she had changed,until she did something that I could not forgive. She harmed my children. Whenever I start to miss her,and believe it or not,she IS my mom,so there are times when I do,when I miss her,I think of my kids,and that sentimental feeling disappears. I told her,basically,you can screw w/me,but you won't srcew w/my kids. She's mentally unstable. I understand why you feel you HAVE to go,but maybe you can leave your kids w/your parents? It doesnt sound like somewhere you would want your kids to be. It would ruin their holiday. If you do have to take them,and it being a holiday I can see where you would,shelter them as much as possible.
Good luck! We are having dinner here,so I'll invite who I wish! Thank God DH's family is normal!