Mustadrak al-Hakim — Hadith 2795

It is narrated from Sayyidah Aishah (may Allah be pleased with her) that she said to Urwah: "O son of my sister, the Messenger of Allah (peace and blessings be upon him) did not favour any of us over another in the time he stayed with us. Rarely did a day pass without him coming round to all of us. He would go close to each wife (and visit her), but he had intimacy only with the one whose turn it was, until he reached the one whose day it was, and there he would spend the night. And when Sayyidah Sawdah bint Zam'ah (may Allah be pleased with her) grew old and feared that the Messenger of Allah (peace and blessings be upon him) might part from her (because of her old age), she said: 'O Messenger of Allah, my day is for Aishah,' and the Messenger of Allah (peace and blessings be upon him) accepted this from her." Aishah (may Allah be pleased with her) said: "It was about this that Allah, the Mighty and Majestic, revealed this verse concerning her and women like her: 'And if a woman fears from her husband aversion or neglect' [Surah al-Nisa: 128]."
This hadith is sahih (authentic) in its chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.