Why would you have to see them? Is there any way you can get out of it? I don't know what your age is so I don't know how essential it is that you follow parental guidelines or if you are an adult and can just do what you want. I hope that this works out for you and that you don't have to be triggered by seeing them. I was abused by my father and I never have to see him again thankfully so I understand the not wanting to see your uncle and his girlfriend. I'm sorry you're having to go through this.