As I see it, a porn addiction is simply a subset of a sexual addiction. Every porn addict that I've ever heard about will masturbate while looking at the porn, and that's a sexual addiction. Plus, in time, every individual who's hooked on porn will find their addiction escalating on them. That means they will move from porn to perhaps the topless or nude night clubs, massage parlors, prostitutes, escort services, or perhaps even on to affairs. The only thing unsure about these kinds of behaviors would be when, exactly, they will become a part of the whole equation. The fact that they will happen is not something that you doubt, particular when you're dealing with a porn or sex addict. The only way to stop these other behaviors from happening is for the addict to get into recovery.

So there's a progression, and affairs are the last stop? Or is there no particular order?

The funny thing about a sex or porn addiction is that the only thing you can count on is that it will progress, but there's no way of telling where that progression will take you, nor is there any way of predicting when the escalation will happen. That means that it is entirely possible that this addiction can turn you into a child molester or a rapist. Of course, it can also take you into sexual anorexia. There's just no way of knowing what will happen until it actually happens.

Another interesting fact about a sexual addiction is that it will continue to progress, EVEN WHILE THE ADDICT IS IN RECOVERY. So, if the addict falls into a relapse, they won't go back to where they were before they got into recovery, but will rather start acting out in the manner they would be using at that time if they had never gotten into recovery in the first place. So that's even more reason for a sex or porn addict to get into recovery, and stay there.