Chiming in a bit late but my .02 cents (from personal experience) is that there are men who are broken and sexually fragmented from an early age, that leads to sexual addiction and an EMOTIONAL emptiness that nothing or no one can fill. Porn, escorts, fetishes, and various expressions of sexual deviance are an expression of that emptiness/void that even a sexy and available wife can't satisfy.
As another poster stated, providers have kept many marriages together - those marriages being the ones where it boils down to a horny/unappreciated/disrespected/ignored/bored husband...
Rinse and repeat.
I was talking to a gent today about this very thing. Our statistics weren't entirely accurate but, I told him that ALL my married clients wanted sexual release (1,500 sperm per second?!? No wonder,guys!) BUT!!! 80% of them crave respect, affection, affirmation, to feel like a woman's hero, and to KNOW they could share at least one sexual fantasy without a wife or gf recoiling or shooting him down.
I wish I could tell wives how many husbands long to tell their wives that. It is never a one partner dance