Sahih Bukhari, Chapter: Witnesses

That he had married Um Yahya bint Abu Ihab. He said. "A black slave-lady came and said, 'I suckled you both.' I then mentioned that to the Prophet (SAW) who turned his face aside." Uqba further said, "I went to the other side and told the Prophet (SAW) about it. He said, 'How can you (keep her as your wife) when the lady has said that she suckled both of you (i.e. you and your wife?)" So, the Prophet (SAW) ordered him to divorce her.