The site doesn't make this guy uncomfortable, per se, it just gives him a little bit of leverage in suggesting or assuming that the OP wants to hop in bed. And honestly, I can see how he is making that connection in his head: girl in my house that has slept with me before, girl has sex like other people hug, same girl is looking at websites that are stimulating to me when I see them over her shoulder, girl is not having sex with anyone else, clearly girl and I should be doing it!

Unless you say something vox, I'd be thining along the same lines as your roommate is right now. I don't think saying something to him means you have to educate the world on BDSM or even get into heavy philosophy to explain and justify yourself, I think it simply means you have a history with this dude and it's time to bring him up to speed on the present situation.

Tell him just what you told us: "I like kinky things, I like the conversations on this site and the friends I have here, and I'm on the site for reasons other than simple sex because, frankly, I'm not wanting to have it right now. After my surgery I'm simply not interested."

Leave it at that.

Or, then next time he looks over your shoulder, click on this thread, put it up on the screen and tell him he should read it.