Nafi' narrates from Abdullah bin Umar (may Allah be pleased with them both): When a man hands over to his wife the authority over her matter, then the decision is whatever she decides, unless he disputes it with her, saying: I intended only one divorce. He swears to that, and the matter is returned to him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20728