These demand curves are the exception rather than the rule, but nonetheless they appear to exist:
One sex worker…explained why she no longer offered her favorite clients free sex or cheaper rates: "They pretend to be flattered, but they never come back!…There was one client I had who was so sexy, a tai-chi practitioner, and really fun to ****. Since good sex is a rare thing, I told him I’d see him for $20 (my normal rate is $250). Another guy, he was so sexy, I told him "**** for free." Both of them freaked out and never returned…They don’t believe they can have no-strings-attached sex, which is why they pay. They’d rather pay than get it for free."
That is from The Purchase of Intimacy, by Viviana Zelizer. I take the main point of this book to be yes you can love your prostitute and perhaps you can like your maid as well. A commercial transaction is compatible with holding deeper feelings for the other party.