Everyone is entitled to their opinion, and yes every person deserves love and attention, and you seem like a nice guy.... but that is just wrong.
Getting kissed on, dry humped, ate out, and then giving a happy ending to 8 different guys a day, multiple times a week, *does* make a girl less "valuable" in the open market. Maybe it sounds a bit harsh to some but it's the truth.
With all other factors being equal, like looks and overall attractiveness, a man will choose the girl that doesn't do spa work over the one that does do spa work every time. And even the spa girls themselves know this. It makes no sense for a guy to willingly choose to deal with the additional baggage that comes along with your significant other doing spa work, when he can just choose a girl that has a job in another industry, an industry that doesn't drive him insane thinking about what she's doing at work.
Even a girl that doesn't have a job would be preferable for a vast majority of men over a girl that does spa work, when looking for a significant other to build a lasting relationship with. All the guys reading this that don't have a cuck fetish know that what i'm saying is 100% facts.