16 y/o DS has been with his girlfriend nearly 2 years now and she does sleep over (he admitted they had sex around 8 months ago). My only condition is that one of them stays in the spare room when she is over, a rule which they have always followed until recently. This was until a month ago... I came in to say goodnight one Saturday when she had stayed and to basically tell him to go to the spare room but I could clearly see they were both clothed & above covers on video chat to other friends, which I was reluctant to interrupt. I'd had a glass (or three!!!) of wine that night and fell asleep before I could return to tell him that he had to go next door, since then they have slept in the same bed every time she's been over. I have told him when she isn't here that I'm uncomfortable with this but he doesn't seem to understand as he's told me that they're having sex, even though I've explained I don't like the thought of them having it in my house!!! How can I get him to move without making her feel uncomfortable??