Think about it: you're paying for a relationship where the terms are at least somewhat defined; you know that you'll be the chief subject of attention (instead of giving out the attention); you get to connect intimately with this person almost immediately, but you don't have to worry about any social obligations when you're not in a session. The terms are pretty clear cut. You are the sole subject of focus. Maybe you're not getting a blow job, but the playing field sure isn't equal.
Oh, but, let's stop talking about me.
Taking the focus off of yourself apparently crosses some kind of professional barrier, but the therapist is expected to at least objectively care about you. It's a fundamentally unbalanced relationship: one person's livelihood combined with another's personal life.
I wonder why it is so acceptable to have this mind mistress or sorts, when it's clearly not to spend some money to obtain a little sexual healing. Isn't prostitution one form of taking care of yourself on one of the most basic levels, uncomplicated by commitment? If someone were to ask me my opinion, I'd probably be an advocate for the decriminalization of prostitution. After all, with legalization comes some level of regulation. Regular STI screenings, more tax money (instead of illicit income), a decreased amount of workplace violence and significantly more comfort reporting it. Legalized prostitution sounds way less sketchy and scary. I wonder why we choose to make it so scandalous and culturally unacceptable.
Sex and psychotherapy - they're both trying to fulfill some pretty basic desires. A therapist will listen and maybe put you on a trajectory to becoming a more emotionally satisfied human being. That kind of relationship seems as (if not more) intimate than a strictly sexual one. Weird.