Having sex with a girl while his roomate was in the room was pretty rude. But honostly, the roomate needs a wakeup call. Thats the thing with roomates. It's a two-way street. You own half of the room, he owns half of the room. You respect him, he respects you. If he sleeps a lot, thats fine. You can go an study elsewhere, and be quiet when you are in there. And if you respect him like that, thats great. But at some point he need to return the favor. He should be totally fine with maybe once a week picking his ass up, and getting a milkshake, and letting you have the room for an hour or two. I think people are looking at this as Sleeping vs. Sex. And since sex is "bad", sleeping wins. He has just as much right to have sex in the room as his roomate has to sleep there.
And personally, you pretty much have to be a complete douche to be like that. I mean I could understand if he was bring chicks home all the time. But like I said, you respect him, he respects you.