One question for the OP. Has the paid sex now replaced what was in the relationship? If the partner isnt asking for sex even on the very limited basis then that is being complicit in the process because somewhere every woman has a friend that will tell them that if their partner isnt pestering them for sex they are getting it elsewhere. Its a truth that a lot of women dont want to face. Once they stop asking they are admitting their partner is getting it elsewhere.
Any woman that prefers that their partner has an affair rather than going the commercial route fails to realise that their partner is just fulfilling a need that they have that is not being met. An affair is oemthgn altogether different. I may have had hundred of punts since my wife started sex refusing but an affair never.
For me, paid sex has always been a poor second to intimate sex with someone I love. I guess my story is familiar to many on this forum - relationship starts with unlimited, varied sex. A couple of kids later and quantity and quality are gradually withdrawn, flimsy excuses being given - I was literally told BJ's were ceasing because OH's friend had stopped giving them to her husband.
Eventually, I had to make a decision - feel free to make your own judgements on my moral standards, but, to me, the path I have chosen has kept our marriage and family unit intact whilst giving me the physical release I need and, indeed, crave.
Your point about pestering the OH for sex opens up some interesting issues. Women want to be desired but also want to be able to say "no" whenever it suits them. Men, generally, would like sex on demand, so a delicate balance is usually established in a relationship which persists until one side decides to change the boundaries. A woman whose husband strays will get plenty of initial sympathy from her girlfriends, but she will also fret about what is being said behind her back as the sisterhood discuss the reasons why her marriage has failed - is he a bastard, or is she being cold?