I just don't think sex with a prostitute sounds fulfilling at all. To me sex isn't just about desiring someone and experiencing pleasure, but also about being desired and giving pleasure. Nothing tops the moment when you look at a woman know she's about to let you have her. Or that stretch when you're first having sex and you just want to be in bed together all day. Or just looking at each other after really good sex. To me those experiences are the heights of life and it would just be impossible to have that with someone who you're paying for sex. All those experiences require a level of mutual desire and obviously a prostitute just desires your money.
I guess, if he has time to see a whore every day or almost every day. But people in relationships can have sex virtually every day if they want to.