Allowing my SO to take our unit for the weekend ?

I am thinking she has no desire to drive there alone. She is trying to force you to go . There is nothing wrong with that. I would go and after set up I would wash the bugs off the front of the trailer and go along with the way the wind blows. Your wife and friends will both recognize they were being unreasonable and it won't come up next year. If it does I'd bet your SO will have a too busy excuse not to go.