According to the definition at Sex Addicts Anonymous, I am not a sex addict because an addict is someone who has trouble with unwanted behavior. I think the most key word in the definition of addiction is "unwanted."
I know I'm extremely oversexed. I know I engage in some risky behaviors. I know I have trouble with monogamy. I know I spend a lot of time masturbating to internet porn. But I'm comfortable with all of this. I don't have a problem with any of it.
I think the real problem with sexual addiction is that people have too much trouble letting go of the pressures that our overly Puritanical society imposes on them to deny their basic urges at all costs and feel guilty about them. If you live out your whole life feeling horribly guilty about wanting to have sex- the most natural thing in the world- then what is the culprit here? Is it your desire to have sex? Or is it the fucked up world that tells you you shouldn't want to? I vote for the latter.
The expectation that we should not masturbate, or have sex with too many partners, or think about sex too much, or be with more than one person at any one time or within a certain time period... is in my opinion very damaging. It leads people to lead double lives, lie about who they are and what they want to themselves and their wives and their families and friends, do even more risky and extreme things to fulfill their urges by binging, and hate other people who act out their own desires that they are unwilling to act on publicly. Lots of other bad things too.