Abdullah bin Bishr narrates from Ayyub al-Sakhtiyani (may Allah have mercy on him) that a mukatab slave had a free woman as his wife. He gave his wife two divorces, then came and asked Uthman bin Affan and Zayd bin Thabit (may Allah be pleased with them both). Both of them answered at once: She has become unlawful for you, because divorce depends on the men.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الرجعة / 15161