Dr. Marty Klein makes a really fascinating argument about the term "sex addiction" in an article in "The Humanist"; that that label  is a way for people not to have to reckon with the conflict between their desire for what certain kinds of sex gives them and the consequences of acting out their desires.    

He goes on to argue that this condition of wanting certain things sexually and not wanting to take responsibility for the consequences is made more troublesome by a sex-negative culture which punishes people for wanting any kind of sex or relationship that isn't socially sanctioned. 

The culture today communicates two out-of-sync messages about sex pretty strongly; one, that we should be ecstatically sexually fulfilled all the time and two, that non-socially-sanctioned sex is highly dangerous and scary (gay, non-monogamous, kinky).  And there is the meta-message which says that commenting on the discrepancy between these two messages -- "Everybody may not be sexually and romantically fulfilled with one, opposite-sex partner for the rest of their lives" -- is not allowed.  A million romcoms have taught us that everyone will end up in a monogamous, same-sex couple and will never feel the desire to masturbate or fantasize about other people or look at pornography because they are so fulfilled.  According to Marty Klein, the label "sex addiction" leaves us stuck in that double bind rather than helping us step out of it.