I want my roommates to not have sex in our house
Why don't you want them to have sex in their own house?
I really hate the noises they make.
They pay to live there, so they can do what they want as long as they are not hurting anyone.
It's not fair. I can't stand it!
If you cannot stand it, maybe listen to music with headphones, or go take a walk. They are being private in their own rooms so you cannot control them.