Musnad Ahmad 287:5

Yahya ibn Sa'id narrated to us, from Ibn Jurayj, from Ibn Abi Mulaykah, who said: Uqbah ibn al-Harith narrated to me—or I heard it from him—that he married Umm Yahya, the daughter of Abi Ihab. Then a black slave woman came and said: "I have breastfed both of you." I mentioned that to the Messenger of Allah, peace and blessings of Allah be upon him, and he turned away from me. I moved to the other side and mentioned it to him again. He said: "How can you [remain with her] when she has claimed that she has breastfed both of you?" So he forbade him from her.