What is the Sharia ruling on divorcing one's wife three times in one sitting, in anger and grief, because she lied about a forbidden relationship that was later discovered? Is it a final irrevocable divorce (baynunah kubra) or a single divorce?

If a man divorces his wife three times with a single utterance, or with three consecutive pronouncements, the correct view is that this counts as a single divorce. This is based on what Muslim narrated from Ibn Abbas (may Allah be pleased with him), that "Divorce during the time of the Messenger of Allah (peace be upon him), Abu Bakr, and for two years of Umar's caliphate, a triple divorce was counted as one." Umar then enforced it as a punitive measure, not as a legal ruling. This is the third view, which holds that it is forbidden, and only one divorce is binding.

However, if a man divorces his wife based on a presumed reason, and that reason turns out to be mistaken, then the divorce does not take effect. An example of this is if he divorces her believing she was unfaithful, and then her innocence is proven; in this case, the divorce does not occur, and he is not considered to have broken an oath.