Is it normal to be disgusted when people make out on your couch?
Long story short, I usually invite my friends over once a week for movie night. Sometimes, one of my female friends brings over her boyfriend, and whenever she does they'll always make out on the couch and I find it quite disgusting when they're all over each other. I don't have a problem with it at all when we're elsewhere (i.e. movies, mall, etc.), but it's a bit uncomfortable when they're on MY couch (or more specifically my parents' couch). The couch always feels a bit contaminated after they leave as well.
Should I say something? Am I valid in my concern? Am I just being prudish? Help please?
PS- I'm single and never had a girlfriend, but I've kissed girls before so I'm not jealous. But I know they're going to bring that up against me if I say anything.