You’re probably right...they deserve each other. The wife got rid of the problem and now the 18 year old has the problem.
The girl lost her father at an early age. I think that has a lot to do with her being infatuation with this teacher. The teacher is a predator and took advantage of the young girl. He also has a responsibility to his wife and children as well as the well being of the students he teaches.
The police should investigate if he had sex with that girl before her 18th birthday.