I used to feel the opposite, actually, Cabrinha! That "just sex" wasn't as bad as falling in love. And I still feel that, in general (although all cheating is abhorrent, of course!), but I now agree with what you say, and more. We can't look at prostitution with any kind of innocence anymore.
This sort of thing frequently gets discussed on the Feminist boards: how much free choice does a prostitute have, really? Even if we can find the tiny percentage of sex workers who aren't forced, trafficked, drugged up, or so financially desperate it's not really a choice, even if we could find that mythical happy hooker, of a.n. act, does she really want to do it? Does she wake up that morning, thinking "I get to do anal today! Woo HOO!"
What you describe as a selling point, that he can get xx or yy actions, techniques from a prostitute, but he doesn't get tenderness and trust and getting to know your lover. Well, that's pretty much the point with men who use them, isn't it? They get their rocks off and don't have to think about the other person. And when he gets xx or yy service from the sex worker, true consent doesn't matter.
We frequently deplore on these Relationships threads men who would have sex with their partner if she isn't enthusiastically consenting - what kind of a man gets off on just using somebody?
Rapists and men who use prostitutes, really.
Sorry, OP, for the hijack.
Hope you're keeping well.