Amr bin Dinar (may Allah have mercy on him) said: I said to Ibn Shihab (may Allah have mercy on him): Abu al-Sha'tha' informed me from Abdullah bin Abbas (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) married while in the state of ihram. Ibn Shihab (may Allah have mercy on him) said: Yazid bin al-Asamm informed me that the Prophet (peace and blessings be upon him) married Sayyidah Maymunah (may Allah be pleased with her) while he (peace and blessings be upon him) was not in ihram, and she was his maternal aunt. I said to Ibn Shihab (may Allah have mercy on him): Do you set a Bedouin who urinates on his heels against Abdullah bin Abbas (may Allah be pleased with him)? She was also the maternal aunt of Abdullah bin Abbas (may Allah be pleased with him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9158