I have heard one too many stupidface "expert" diagnose someone with sex addiction because the guy likes to sleep with a lot of people, or wants to be in multiple relationships, or cheats.
If you're a cheater, you're a cheater. Sure you could be a sex addict, but it's an entirely separate issue.
Want to sleep with lots people or be in multiple relationships? GREAT HAVE FUN. My life is a hundred thousand times more fulfilling with my multiple romantic and sexual relationships. Sex addiction has NOTHING TO DO with your number of partners.
I think I did have a kind of sex addiction, or more accurately, a kink addiction, where I was using D/s relationships to satisfy an unhealthy need or to gloss over actual problems in my life, kind of like other people use alcohol or drugs or food. Guess what? I had one partner at a time then. When I met Simon, I think I was ready to use him in the same way, but he didn't let me, because he focused on showing me my own value and wouldn't let me use our relationship to cover things up or prove the bad things I thought about. He supported me confronting the problems I was using D/s to avoid and you know what happened? I married him. And I have fabulous sex with many people* and am blissful I tell you. Blissful. So fuck you, experts.
*And am also married to another fabulous person who helps me believe in myself and keep me from going to that bad place again every day so there