What is the reason for the descend of Surah at-Tahrim?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

There are two reasons narrated in Ahadeeth for the revelation of Soorah At-Tahreem [Quran 66].

‘Aa’ishah narrated that the Prophet used to stay (for a period) in the house of Zaynab bint Jahsh, may Allaah pleased with her, (one of the wives of the Prophet) and he used to drink honey in her house. Hafsa (may Allah pleased with her) and I decided that when the Prophet entered upon either of us, she would say, "I smell in you the bad smell of Maghafir (a bad smelling raisin). Have you eaten Maghafir?" When he entered upon one of us, she said that to him. He replied (to her), "No, but I have drunk honey in the house of Zaynab bint Jahsh, and I will never drink it again." Then the following verse was revealed (which means): {O Prophet, why do you prohibit [yourself from] what Allah has made lawful for you, seeking the approval of your wives? And Allah is Forgiving and Merciful. Allah has already ordained for you [Muslims] the dissolution of your oaths. And Allah is your protector, and He is the Knowing, the Wise. And [remember] when the Prophet confided to one of his wives a statement; and when she informed [another] of it and Allah showed it to him, he made known part of it and ignored a part. And when he informed her about it, she said, "Who told you this?" He said, "I was informed by the Knowing, the Acquainted." If you two [wives] repent to Allah, [it is best], for your hearts have deviated. But if you cooperate against him - then indeed Allah is his protector, and Gabriel and the righteous of the believers and the angels, moreover, are [his] assistants.} [Quran 66:1-4]

The two were 'Aa’ishah and Hafsah . Also, the Statement of Allah: {And [remember] when the Prophet confided to one of his wives a statement…}; i.e., his saying, “But I have drunk honey.” Hisham said: “It also meant his saying, “I will not drink anymore, and I have taken an oath, so do not inform anybody of that.” [Al-Bukhari]

There is another reason for the descent of Soorah At-Tahreem

Imam Ibn Hajar narrated in his known book Fathul-Baari that Imam An-Nasai’i narrated through a sound chain from Anas that Hafsah said: “The Prophet had a female slave and he used to have sex with her. Hafsah the wife of the Prophet kept on insisting that he gives up going to that woman slave till he agreed with her and even made her forbidden to him. Then Allah descended the above Soorah.”

If more than one authentic narration is given citing the reason for the revelation of a Soorah, the scholars accept them as reasons for the Soorah being revealed more than one time.

Allah knows best.