What is the ruling regarding a man saying to his wife during her menstrual period: "By triple divorce, you are not leaving, and if you leave, you will be divorced," if the wife does not leave after this statement?

It appears that your statement, "If you go out, you are divorced," is a confirmation of a conditional divorce oath tied to the wife's departure. Our fatwa (definition) is that divorce occurs irrevocably (three pronouncements) if she breaks it. The breaking of the oath occurs when the wife departs in the manner intended by the oath. If the intention was to absolutely prevent her departure, then she breaks the oath with any departure. However, if it was restricted to a specific time or place, then she does not break the oath by departing outside of that restriction. The conditioning of the divorce during menstruation does not prevent the occurrence of divorce upon the breaking of the oath. It should be noted that the lawful oath is by Allah, and swearing by divorce is among the oaths of the dissolute and has severe consequences, especially if it involves the word "three."