Same as anything it's about getting the right balance.
Some people have what was described to me as "an addictive personality" which means they are prone to doing things to excess and the brain produces "reward" drugs such as dopamine that are potentially more addictive than heroin etc, there is also evidence that this can partly be genetic.
like any addictive drug you need a bigger and bigger dose to satisfy the craving, likelihood is that this guy would have become addicted to something else if he hadn't found porn and escorts first.
Not quite sure why he didn't become a porn star if he had the opportunity as this would have satisfied his habit and paid him at the same time, his basis that it would "ruin his reputation" seems strange now that he has gone on record so he is now out as a porn addicted prossie shagger which surely has a bit less kudos than being a porn star stud?