I need an out from tomorrows gathering.

I just had an argument with my hubby and we have a family gathering tomorrow I really don’t want to go to bc then we have to pretend everything is ok. I’ve done it too many times and it’s not fun. What’s a seemingly legit reason I can get out it, if not completely, then to leave early bc we are supposed to spend the night. (Anyway I hate their dog even though I’m an animal lover. The thing sucks the life out of me the entire time.)