What is the ruling regarding a man who said to his wife, "You are divorced, and forbidden to me as long as I live," intending to safeguard himself from immoral acts, but then committed them? Is expiation for breaking an oath (kaffarat al-yameen) required of him, and is the expiation repeated with the repetition of the sin?

We have previously explained the ruling on conditional divorce (ta'liq al-talaq) and rendering the wife unlawful upon the occurrence of an event, and the scholarly differences concerning it. If the conditional divorce is not intended as a divorce, then it is an oath (yamin), and an expiation for an oath (kaffarat yamin) is sufficient for breaking it. The same applies to rendering the wife unlawful if an oath is intended by it. Your statement "as long as I live" does not necessitate the repetition of the condition, so the oath is dissolved upon the fulfillment of the condition for the first time. The disagreement on this issue is strong and ancient, and most scholars hold the view that the divorce becomes binding. We advise against swearing by divorce.