Musnad Ahmad 1156:34

Yahya ibn Sa'id narrated to us, from Sufyan, who said: Muhammad ibn Abi Bakr narrated to me, from 'Abd al-Malik ibn Abi Bakr, from his father, from Umm Salamah, that when the Messenger of Allah (peace and blessings of Allah be upon him) married her, he stayed with her for three days and said: "It is not the case that you are held in low esteem by your family. If you wish, I will stay with you for seven days, and if I stay with you for seven days, I will stay with my wives for seven days."