I'm going to disagree here a bit.
Disclaimer:
I'm not a professional anything.
My experiences with my addict do not imply that your have an addict.
now then.........
My ex had the same compulsion for sex that she did for alcohol. If you use the term addict by definition, she was a sex addict. I can view it as a compulsion ....the semantics of the words matter not.
In my case, I found that no matter what she got sexually with me (and I am am pretty widely varied and open minded sex partner), she still needed to get a "fix" with whomever, whenever and however she needed to.
I mean it literally was....I'd leave her house, and before I got home to my house, she was online looking for a hookup.....and getting them. Went on for months....I never knew. Never suspected. This activity was always joined with consumption of alcohol. She would tell you in no uncertain terms she was as happy as could be and was in sheer bliss with me.....yet when I left.......
I'd often need to travel with work or so did she. I later learned that literally while you were talking on the phone about missing her......she was in the process of finding sex partners. She traveled to a job interview.....out of state....and I later discovered that she hit the local C/L ads and met multiple men as a result. Of course denying it all when asked and even when you present computer evidence that you KNOW is theirs.....only results in....How could you invade my privacy....rants. Just like alcohol addiction!!!!!
In the end it all (all reckless behaviors) stemmed from some underlying issues of self worth they face. If they turn to alcohol etc., you can label it addiction if you like. Either way what you are dealing with is something that causes them to set judgement and rational (to us) thinking aside, to pursue the compulsion, to fill the void. It becomes an ever deepening spiral. First its a minor stray from the norm.......to eventually they have to feed ever more to ever deepening hole. Doesn't matter how much they get, it won't be enough.
By the time my relationship was over with my ex, I became terrified of sex. And trust me coming from a guy like me....that was a journey I NEVER expected to be taking. The things she did, under the circumstances she did them, were enough to make you physically ill (well it did me anyway).