This post of yours has a density to it I think would be interesting to respond to. You have delineated in a way from what is more often smoothed over together. The point if sex gives the SP for work or not sexual pleasure is actually germane. And it is not just a "typical guy" whom may have problems, for of course in my personal experience it is the "typical" (hate that word though) woman has a hard time decoupling sexual acts from emotional attachment, which is really more natural for most people in an emotional relationship - and there is nothing wrong with that per se. I mean to say that it is very normal for most people that express a vulnerable emotional attachment to another that sexual intimacy and pleasure from it gets possessive. Nothing wrong with that either, it is though a choice for those emotionally mature enough in realizing this dynamic of being human.
I cannot imagine you are saying then that any climax or orgasm you have while working is only about "performing". Which yes from a strict definition in a work setting I agree is - but for someone in a relationship that mere point of someone else giving the other such pleasure still can be an issue, especially if as the SP you are saying that the other in the relationship cannot seek that also for themselves, but only if they were in the same line of work? So it is only for "performance" they can have the sometimes actual climax and feelings of pleasure from another - unless you are saying it never happens for you and the sexual pleasure is only a performance and you don't feel anything really.
Now I say this not necessarily advocating the point all from personal belief, but because I love to say "for the sake of argument".
I agree, simplicity would be to remain single while still working in the sex trades. It would be a challenge for sure for a truly monogamous relationship.