Yazid bin al-Asamm (may Allah have mercy on him), who was the son of the sister of Maymunah (may Allah be pleased with her), said that the Messenger of Allah (peace and blessings be upon him) married Maymunah (may Allah be pleased with her) while he was not in ihram.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14202