It is narrated from Hazrat Aisha that sometimes ghusl (ritual bath) would become obligatory upon the Prophet (peace be upon him), and the Prophet (peace be upon him) would return to his wife again without touching water with his hand.
Hadith Referenceمسند احمد / مسند النساء / 24778
Hadith Gradingحکم دارالسلام:رجاله ثقات غير شريك، وهو سيئ الحفظ، ولكن تابعه سفيان كما فيي الرواية: 24755