What is the legal status if a revocable divorcee marries another man, that man has intercourse with her, and then the first husband reconciles with her before the first Iddah expires?
General Chapter
Al-Mughni
Book of Reconciliation (Return During 'Iddah)
Primary text
If the original husband reconciles with his revocable divorcee while she is unaware of the reconciliation, the reconciliation is valid because it does not require her consent, just as divorce does not require her knowledge. If he reconciles, her Iddah expires, and she marries another man, and subsequently, the first husband proves by evidence that he had reconciled before her Iddah expired, her status as his wife is established, and the second marriage is void because he married a woman who was already someone else's wife. She is returned to the first husband whether the second husband had intercourse with her or not. This is the correct view, held by the majority of jurists, including Al-Thawri, Al-Shafi'i, Abu Ubayd, and the Ashab al-Ra'y, and it is narrated from Ali (may Allah be pleased with him).
Supporting text
There is a second narration from Abu Abdullah (may Allah have mercy on him) stating that if the second husband had intercourse, she becomes the wife of the second husband, and the first marriage is voided. This is narrated from Umar ibn al-Khattab (may Allah be pleased with him) and is the position of Malik, with similar narration attributed to Sa'id ibn al-Musayyab, Abd al-Rahman ibn al-Qasim, and Nafi'. Their reasoning is that both men validly contracted marriage with her, and the second husband has the added element of consummation, giving him precedence. Our proof is that the reconciliation was valid, and she married while she was still the wife of the first, rendering her second marriage invalid, as if he had not divorced her at all.