Hadithcore
Mishkat al-Masabih, 2695

Abu Rafi‘ said:

God’s messenger married Maimuna when he was not in the sacred state and cohabited with her when he was not in the sacred state, and I was the messenger between them. Ahmad and Tirmidhi transmitted it, the latter saying that this is a <i>hasan</i> tradition.

قَالَ: تَزَوَّجَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَيْمُونَةَ وَهُوَ حَلَالٌ وَبَنَى بِهَا وَهُوَ حَلَالٌ وَكُنْتُ أَنَا الرَّسُولَ بَيْنَهُمَا. رَوَاهُ أَحْمَدُ وَالتِّرْمِذِيُّ وَقَالَ: هَذَا حَدِيثٌ حَسَنٌ

References1 variant
In-Book Reference
Book 10, Hadith 185