I lost one Karate School to Sex. Mind you, I had had schools in a number of places, usually they did pretty well, and i loved teaching, so I was sort of stunned when one self destructed.
This was up in Santa Rosa in the eighties. I had a dozen students, things were growing, and suddenly, within the space of a month, I had nothing.
A couple of months later I happened across one of my errant students and got the story.
There was a fellow who was using the school as a dating service. He moved from female student to female student, dated them, dumped them, and the girls didn’t want to come to class anymore.
And, this cancer seemed to infect even the male students. I guess they just felt the down curve of the whole thing and left. And, the source of his prey destroyed, the sex fiend moved on. And I hadn’t even a clue as to what had happened. Grrr.
I am reminded of the Zen parable wherein an attractive nun keeps getting notes from a secret admirer asking her to meet him some dark night. She stands up in front of the nuns and monks and reads the note aloud, then asks whoever wrote the note to come embrace her in daylight.
Secrets. Secrets of the soul.
Why is something a secret? Because somebody is hiding something they should be ashamed of.
Have you ever considered the root of the word Hell? It means something that is hidden. Have a nasty secret and you are opening the door to hell, and right here on good old planet earth.
I am more aware these days, and I make it public and certain knowledge that if you’ve signed up in my karate school, then you’re there to learn martial arts. I don’t run a dating club, and anybody who disagrees is quickly and without hesitation shown the door.
I teach more than just Karate at Monster Martial Arts.
Matrix Martial Arts 
Only the instructor should be allowed to date the students..haha. Funny thing I dated a female student when I was a student and then later dated another and married her, still married 28 years later.