I strongly recommend you listen to Dr Drew's radio show Loveline (mp3's can be found here http://www.lovelinearchive.com/ for a while at least). He's an actual doctor, not a radio doctor, and he has been taking calls on sex and addictions for over 10 years, and the subject of stripping/porn acting/prostitution comes up regularly. Basically, anyone working in the sex industry believes they are just doing it for the money, or it's what they want, but invariably they suffered some sort of tramua as a child, sexually abused by a family member usually. Now stripping is on the light end of this spectrum, so I wouldn't want to say I know what's going on in your roommate, or his student's mind. But people who have sex with strangers on film are not "perfectly normal", and do not have stable happy lives. It's worth bearing in mind that we as humans are really bad at understand just what it is that motivates us. But again, do not take my word for it. It is actally amazing how much Dr Drew can tell from a caller, just from talking to them for a minute or so.

Thomas.