Musnad Ahmad 1153:738

'Abdullah ibn Yazid narrated to us, from Sufyan, and he mentioned another man, from Sufyan, from Abu Ishaq, from al-Aswad, from 'Aishah, who said: "The Messenger of Allah (ﷺ) would have intercourse with his family at the beginning of the night, then he would sleep and not touch water. Then, when he awoke at the end of the night, he would return to his family and perform ghusl (ritual bath)."