What's there even to talk about? You offered them a room, and they are lovers—you know it. You should have been aware of the consequences of letting two love birds stay in the same room all night. They even tried to muffle the noise, and the door is shut and locked. Will you scold them for not being considerate to their other friends? That thank goodness it was you who heard those noises behind the door and not anyone else? That what if someone else had heard them? You are all adults, so you should have a proper sense of privacy and understanding of the situation. Fucking annoying nosy piece of shit.