Does a divorce occur if the husband suspects his wife of future infidelity, knowing that he told her jokingly: "If the day comes when I truly doubt you, you will no longer be my wife"?

The phrasing used with the wife, "If you do such and such, then you are not my wife," is considered a metaphor (kinayah) and not an explicit divorce. Divorce does not occur with metaphors unless there is an intention to divorce. Therefore, as long as you did not intend to make the divorce contingent upon doubting your wife, no divorce occurs. One must think well of his wife unless suspicion arises, and it is impermissible to utter such offensive phrases and engage in ugly jesting with her. Rather, one must live with his wife with kindness and good words.