Sahih Muslim
The Book of Menstruation (Kitab Al-Haid)
Book Number: 003 / Hadith Number: 685
'A'isha the wife of the Apostle of Allah (may peace be upon him) reported. A person asked the Messenger of Allah (may peace be upon him) about one who has sexual intercourse with his wife and parts away (without orgasm) whether bathing is obligatory for him. 'A'isha was sitting by him. The Messenger of Allah (may peace be upon him) said: I and she (the Mother of the Faithful) do it and then take a bath.