When Muhammad came to Medina, he was very poor and had nothing with him. He made a mosque and a small house adjacent to it for himself and his one wife Sawda. However, soon Muhammad was involved in wars and became rich, and he married multiple women and had several concubines. Nevertheless, his house didn't become big enough to accommodate all of his new wives and concubines. 

One day, Muhammad asked Hafsa to visit her father. With Hafsa away, Muhammad took advantage of the opportunity and had intimate relations with Mariyah in her room. However, Hafsa returned unexpectedly and caught her husband in the act with Mariyah in her bed, causing her great distress. She loudly expressed her anger and disbelief that Muhammad could send her to her father's house in order to have intimate relations with Mariyah (although it was the turn of Hafsa). In response, Muhammad tried to appease her by taking an oath to never touch Mariyah again and begged her to keep the matter private.

However, Hafsa could not contain herself and shared the incident with Aisha, who joined forces with all the other wives to cause the Prophet further suffering.

Actually, 'Aisha was already extremely angry with Muhammad and she was doubting his prophethood and the Revelation. 

Sahih Bukhari, 5113:

Khaula bint Hakim was one of those ladies who presented themselves to the Prophet for marriage. `Aisha said, "Doesn't a lady feel ashamed for presenting herself to a man?" But when the Verse: "(O Muhammad) You may postpone (the turn of) any of them (your wives) that you please,' (33.51) was revealed, " `Aisha said, 'O Allah's Messenger! I do not see, but this, that your Lord hurries in pleasing you (by sending revelations quickly on the spot)' "

Please also read this article to know why 'Aisha was angry with Muhammad: The role of REVELATION in Muhammad's journey from 4 marriages to 9 marriages

So, firstly Muhammad postponed the turns of wives with the Help of Revelation. And then on their turns, he was also having sex with his concubines. 

When 'Aisha further told others and all of his wives became aware of how Muhammad was having sex with the concubine Mariyah, while it was the turn of Hafsa, Muhammad became furious. As a result, Muhammad decided to abstain from interacting with all his wives for a period of one month as a form of punishment. And he also found a way to break his oath. Thus, he claimed the revelation of the following verse from Allah:

Verse 66:1-5:

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 (Hafsah) a statement; and when she informed [another i.e. 'Aishah] 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. Perhaps his Lord, if he divorced you [all], would substitute for him wives better than you - submitting [to Allah], believing, devoutly obedient, repentant, worshipping, and traveling - [ones] previously married and virgins.
Anas reported the following incident regarding the revelation of these verses:

Sunan Nisai, Hadith 3959:

It was narrated from Anas, that the Messenger of Allah had a female slave with whom he had intercourse, but 'Aishah and Hafsah would not leave him alone until he said that she was forbidden for him. Then Allah, the Mighty and Sublime, revealed: "O Prophet! Why do you forbid (for yourself) that which Allah has allowed to you.' until the end of the Verse.
Grade: Sahih (authentic)

This story is also reported by Ibn Sa’d in Tabaqat:

Waqidi has informed us that Abu Bakr has narrated that the messenger of Allah (PBUH) had sexual intercourse with Mariyah in the house of Hafsah. When the messenger came out of the house, Hafsa was sitting at the gate (behind the locked door). She told the prophet, O Messenger of Allah, do you do this in my house and during my turn? The messenger said, control yourself and let me go because I make her haram to me. Hafsa said, I do not accept, unless you swear for me. That Hazrat (his holiness) said, by Allah I will not contact her again. Qasim ibn Muhammad has said that this promise of the Prophet that had forbidden Mariyyah to himself is invalid – it does not become a violation (hormat).

Reference: Tabaqat v. 8 p. 223 Publisher Entesharat-e Farhang va Andisheh Tehran1382 solar  h ( 2003) Translator Dr. Mohammad Mahdavi Damghani

Umar Ibn Khattab also made it clear that it were Hafsa and 'Aisha for whom these verses were revealed. 

Sahih Bukhari, 2468 and Sahih Muslim 1479e:

Narrated `Abdullah bin `Abbas:

I had been eager to ask `Umar about the two ladies from among the wives of the Prophet (ﷺ) regarding whom Allah said (in the Qur'an saying): If you two (wives of the Prophet (ﷺ) namely Aisha and Hafsa) turn in repentance to Allah your hearts are indeed so inclined (to oppose what the Prophet (ﷺ) likes) (66.4), till performed the Hajj along with `Umar (and on our way back from Hajj) he went aside (to answer the call of nature) and I also went aside along with him carrying a tumbler of water. When he had answered the call of nature and returned. I poured water on his hands from the tumbler and he performed ablution. I said, "O Chief of the believers! ' Who were the two ladies from among the wives of the Prophet (ﷺ) to whom Allah said: 'If you two return in repentance (66.4)? He said, "I am astonished at your question, O Ibn `Abbas. They were Aisha and Hafsa."

... The Prophet (ﷺ) did not go to his wives because of the secret which Hafsa had disclosed to `Aisha, and he said that he would not go to his wives for one month as he was angry with them when Allah admonished him (for his oath that he would not approach Maria). When twenty-nine days had passed, the Prophet (ﷺ) went to Aisha first of all. She said to him, 'You took an oath that you would not come to us for one month, and today only twenty-nine days have passed, as I have been counting them day by day.' The Prophet (ﷺ) said, 'The month is also of twenty-nine days.' That month consisted of twenty-nine days ... 

Now this story made Muslims uncomfortable, while Muhammad did not look like a good person here:

  • He first married multiple wives with the help of Revelations.
  • And then he started postponing their turns with the help of the revelation.
  • And then he also started having sex with his concubines, neglecting their turns. 
  • And when his wives protested upon it, he threatened them extremely hard with divorce and Jibrael and Allah being his protector. 
  • And he made concubines again Halal for himself by using the Revelation.

People can easily become doubtful about Muhammad after looking at it (i.e. he used to make the revelations on his own for his personal interests). Even 'Aisha became doubtful and told Muhammad that Allah hastens in fulfilling his sexual desires. 

Islamic apologists were also unable to deny this Hadith about this incident, as the Quranic verses were also present which were a witness to this incident. Thus, they fabricated another Hadith, which claimed another incident about the revelation of these Quranic verses. 

Sahih Muslim, 1474a:
'A'isha (Allah be pleased with her) narrated that Allah's Apostle (ﷺ) used to spend time with Zainab daughter of Jahsh and drank honey at her house. She ('A'isha further) said: I and Hafsa agreed that one whom Allah's Apostle (ﷺ) would visit first should say: I notice that you have an odour of the Maghafir (gum of mimosa, whose odour is unpleasent). He (the Holy Prophet) visited one of them and she said to him like this, whereupon he said: I have taken honey in the house of Zainab bint Jabsh and I will never do it again. It was at this (that the following verse was revealed): 'Why do you hold to be forbidden what Allah has made lawful for you... (up to). If you both ('A'isha and Hafsa) turn to Allah" up to:" And when the Prophet confided an information to one of his wives, and when she informed [another i.e. 'Aishah] of it and Allah showed it to him, he made known part of it and ignored a part." (Verse 64:3). This refers to his saying: But I have taken honey.

This is known as "The Incident of Honey". And this is a fabrication. And the proof is present in this tradition itself, i.e.:

  1. Firstly this tradition claims that 'Aisha and Hafsa JOINLTY made this conspiracy against Muhammad to tell him that they noticed the unpleasant odour of Maghafir from his mouth. Please see these words of this Hadith: "...  I and Hafsa agreed ... "
  2. But the verse 64:3 is clear that it was not a JOINT conspiracy. No, but Muhammad first told it to one wife (i.e. Hafsa), and later she informed another wife (i.e. 'Aisha). Thus, this part of the verse does not fit any "joint conspiracy", but it supports only the incident of Mariyah. 
  3. Moreover, verses 64:1-5 do not threaten the two wives for any "joint conspiracy", but threaten one wife for telling Muhammad's secret to another wife.
  4. Moreover, in the incident of honey, only Hafsa and 'Aisha were involved, but all of his wives were involved only in the incident of Mariyah, where Muhammad vowed not to go to any of them for one month (Sahih Bukhari, 2468 and Sahih Muslim 1479e)

Islamic apologists fabricated Ahadith to save the honour of Muhammad and Islam, but they were not PERFECT in telling a lie. They were caught due to contradictions in their lie. 

Moreover, this contradiction increases further, as there exist similar Sahih Ahadith about the incident of honey (from the same 'Aisha), except the roles of the characters are reversed. So instead of Zaynab, it was HAFSA who gave honey to Muhammad to eat, while other wives conspired against Hafsa. Meaning there exist multiple authentic narrations of the same story of honey that contradict each other.

Sahih al-Bukhari 5268 and Sahih al-Bukhari 6972:

Narrated `Aisha:

Allah's Messenger (ﷺ) used to like sweets and also used to like honey, and whenever he finished the `Asr prayer, he used to visit his wives and stay with them. Once he visited Hafsa and remained with her longer than the period he used to stay, so I enquired about it. It was said to me, "A woman from her tribe gave her a leather skin containing honey as a present, and she gave some of it to Allah's Messenger (ﷺ) to drink." I said, "By Allah, we will play a trick on him." So I mentioned the story to Sauda (the wife of the Prophet) and said to her, "When he enters upon you, he will come near to you whereupon you should say to him, 'O Allah's Messenger (ﷺ)! Have you eaten Maghafir?' He will say, 'No.' Then you say to him, 'What is this bad smell? ' And it would be very hard on Allah's Messenger (ﷺ) that a bad smell should be found on his body. He will say, 'Hafsa has given me a drink of honey.' Then you should say to him, 'Its bees must have sucked from the Al-`Urfut (a foul smelling flower).' I too, will tell him the same. And you, O Saifya, say the same." So when the Prophet (ﷺ) entered upon Sauda (the following happened). Sauda said, "By Him except Whom none has the right to be worshipped, I was about to say to him what you had told me to say while he was still at the gate because of fear from you. But when Allah 's Apostle came near to me, I said to him, 'O Allah's Messenger (ﷺ)! Have you eaten Maghafir?' He replied, 'No.' I said, 'What about this smell?' He said, 'Hafsa has given me a drink of honey.' I said, 'Its bees must have sucked Al-`Urfut.' " When he entered upon me, I told him the same as that, and when he entered upon Safiya, she too told him the same. So when he visited Hafsa again, she said to him, "O Allah's Messenger (ﷺ)! Shall I give you a drink of it (honey)?" He said, "I have no desire for it." Sauda said, Subhan Allah! We have deprived him of it (honey)." I said to her, "Be quiet!"

One lie requires a hundred more lies to cover it up, but the lie still manages to get exposed.

It is strongly requested that please also read the related article: The Hadith Fabrication Factory of Muslims: 131 Traditions claimed it was Ishaaq who was slaughtered, while 133 Traditions were fabricated that claimed it was Ismael who was slaughtered