Dating your student
Even though you used to walk into your home with your shoes on, and sit on your bed in the same clothes you just wore while riding the subway, or sat on a public bench in, you'll become far too disgusted to ever do it again. They'll make you hyper-aware that germs are everywhere and on everything.
Student/teacher happens a lot in real life, especially in North America. it is only a "thing" here in the US when it's found out, but teacher/student stuff happens every day and I remember when I was in school, hearing rumors that it happened.On the other hand, the guys in the business school were surrounded my mostly other men in their classes.Online dating helped them meet students of the opposite sex at their school.Regardless of age of consent, it's still considered an abuse of authority.
What you're seeing here is just another anime/manga/visual novel trope.A teacher keeping their job would be the only issue.