The best teacher is personal experience, but it's expensive.
However, some of us just never learn from errors they have made.
I mean, many people, having once made a mistake in choosing a partner, seek the same personality type over and over again.
Why? Where does this masochism come from?
For example, a young man in his late teens fell in love with a femme fatale. The relationship didn't work out, and the guy was badly burned. But, after that, he tried to create a serious relationship with the woman similar to his ex. Obviously, all these attempts failed.
We are attracted to the familiar type, since something already discovered seems to us the most pleasant, sympathetic, almost native. And often, this is not the case.