I never felt comfortable bringing a partner home to sleep at my parents' house, and was shocked a few year ago when I found out that my niece was "allowed" by her parents to stay with her boyfriend at what I considered a very young age - 17. It was only when talking about it with my mother, that I realised she was doing exactly as I had done. In my case, my parents spoke with my partner's parents about the set-up, which was a bit of a farce in reality, but obviously made them feel better about the situation.
My sister on the other hand, installed a few guys over the years, and basically completely abused our parents - trashing the room, eating them out of house and home etc. I came home one night to find my father and the then bf having a massive row, which was fast going bad, and I stepped in and broke it up. I told the bf that he was out of order, and that while he was sleeping under someone else's roof, he should show some respect. I got called a "jumped up tart" and he and my wayward younger sister moved out the following day.
Prior to that, I recall once arriving home from a club and my father calling down the stairs asking which of us it was. I replied "me", to which he responded "Where is your sister?" so I told him "Outside in the back of a car", omitting the fact that the car door was open and it was very clear what they were doing. Had it been me he would most likely have gone outside and dragged me indoors, but as it was her, he turned over and went back to sleep.
Times have changed, sadly sex so often seems to be more of an "activity" rather than something that goes on between two people who care about and respect each other. I like to think that if my child were in such a relationship, I would accommodate that and ask that there was a mutual respect in the circumstances. I think there need to be ground rules/safe sex chat etc, but at such an age, I'd prefer that they had somewhere safe to share private time, rather than be in a car or round the back of a club etc.
Everyone's different, and it is your home and you have your beliefs, so it is a decision only you and your family can make. I hope that you can reach an agreeable compromise so nobody is uncomfortable in their own home.