What should a husband do with the teacher who tried to get to know his wife, and is it permissible for him to hit or harm him, taking into consideration that reporting to the authorities might cause a scandal for the wife?

The husband is not allowed to beat or harm the teacher, as discipline (ta’deeb) and punishment (ta’zeer) are the right of the ruler, not individuals. If the teacher resumes calling or messaging the wife, the husband should report him to someone who can deter him. The husband must protect his wife and prevent her from suspicious mixing with men.