"Sex Addiction" - give me a break ...
Sex is not an addiction any more than skating backwards is. It may feel good to have air blowing up your behind (or to have sex) but that does not an addiction make. And if you feel you are addicted, just stop skating backwards!
The problem is that calling it an "addiction" trivializes addictions which are real and substantive. The operative word being "substantive" meaning there is a substance involved (although this may not be the correct usage of the term substantive).
With real addictions be it alcohol, drugs, nicotine or prescription drugs, there is always a substance at work which makes us feel a certain way ("good" or at least "better" than without it). From that emerges an addiction to that "feel good effect" and in that sense, yes, food can be an addiction also but sex cannot.
Of course sex feels good, it is supposed to and without it feeling good there would be a risk of the species becoming extinct. Therefore, it is a natural and fundamental instinct to want to have sex and not so to want to smoke or take Vicodin.
But the individuals claiming "sex addiction" are not having "more of a good feeling" then the rest of us, they just have more opportunities. Maybe I just don't know but the "problem" of sex addiction does not seem to afflict a whole lot of broke, unattractive men. It seems to be a disease of the rich and not entirely physically repugnant men such as Tiger Woods or David Duchovny.