Musannaf Ibn Abi Shayba 9:822

Jarir narrated to us, from ‘Ata’ ibn al-Sa’ib, who said: A man came to Ibrahim and said: He married a woman whose husband had been reported dead to her, then a letter came from him [stating] that he was alive. He said: Ibrahim said: "Separate from her. If he arrives, then if he wishes, he may choose [to keep] what he gave her as a dowry, and your wife remains in her state. But if he chooses the woman, then when her waiting period from you has ended, she is the wife of the first [husband], and she keeps what he gave her as a dowry in exchange for what he enjoyed of her private parts." He said: "May I eat with her?" He said: "Yes, but do not enter upon her until you have informed her."