The prohibition of marriage for one who is in Ihram, and it is disliked for him to propose marriage Sahih Muslim 1411
Translation
Yazid b. al-Asamm reported
Maimuna daughter of al-Harith narrated to me that Allah's Messenger (ﷺ) married her and he was not in the state of Ihram. And she (Maimuna) was my mother's sister and that of Ibn 'Abbas (Allah be pleased with them).