Musnad Ahmad 1153:1396

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, and Hajjaj said: Shu'bah informed us, from Mansur, from Ibrahim, from Alqamah, from Aisha: "That the Messenger of Allah, peace and blessings of Allah be upon him, used to engage in physical intimacy (mubasharah) while he was fasting."