Sex addiction is a process addiction like gambling, compulsive over eating, spending and workaholism. The difference between these process addictions and substance addiction is that with substance addiction (alcohol, cocaine, etc.) you can put the substance down. But sexuality is an innately powerful part of identity. For sex addicts their behaviors have affected their self-esteem and identity as well as relationships with others.
Recovery from sex addiction and the other process addictions is different because the addictive behavior revolves around good and necessary parts of life (food, sex, and work). Total sobriety from the behavior is not the goal. The goal is to have a healthy relationship with the behavior.
For sex addicts the source is always available. While a person addicted to a substance must go pick up the substance and ingest; the sex addict always has the source readily available in their mind.
Because the sex addict carries the source of their addiction with them, they have to work on both outward sexual behaviors as well as what they do in the privacy of their own mind.
In surveys of recovering sex addicts with at least 5 years in recovery, the three things they report as being most helpful are: (1) 12 step groups (2) Getting a sponsor and working the 12 steps and (3) Finding a therapist who understands sex addiction.