First let's see the ayah regarding the marriage between Muhammad and the wife of his adopted son Zayd. Read Quran 33:37
In this ayah, we can see that Allah is the one who marries Muhammad and Zaynab.
Did you read through the sentence "So when Zayd had no longer any need for her, We married her to you in order that there not be upon the believers any discomfort concerning the wives of their adopted sons WHEN they no longer have need of them."
My first question is that what kind of a need do Muslim husbands have with their wives after that they are no longer needed? Will anyone consider their wife as something that they use and throw? What will we call such people?
And why Allah married her to Muhammad? It is for allowing the Muslims to marry their adopted sons wife they have WHEN they have no longer need of her.
Isn't that husband a procurer for his adopted father?
Also, read the Tafsir of this verse 33:37 of Al-Jalalayn
From the verse itself we can get to know that, Muhammad has hidden his hearts desire of marrying Zaynab and he only disclosed when Allah revelead it as ayah.
Why did he hide it? Because people will say that "He has married his son's wife!" So people at that time has higher morality that it is not a GOOD PRACTISE to marry and consumate an adopted son's wife.
Did you see that, Zayd is considered as his own son. Read the Sahih Jami` at-Tirmidhi 3209
So why did Allah married Zainab to Muhammad, the real answer is that Muhammad saw the adopted son's wife naked and he felt love for her body.
Was she naked? Let's check that.
For that we will get to know the full story what really happened.
Here we can see that Zaynab only considered Muhammad as a father and mother not as a sexual partner.
And after this incident happened (seeing Zaynab naked by Muhammad), Zaynab explains this scenario to her husband Zayd; Zayd understood that "...perhaps Zaynab has excited your (Muhammad's) admiration , and so I (Zayd) will separate myself from her."
Is this how Zayd had no longer any need for Zaynab according to the Quranic verse 33:37 ?
So after these incidents happened Allah revelead ayah to Muhammad maybe with a ringing of a bell as mentioned in https://sunnah.com/bukhari:2
Muhammad smiled 😉, he is happy now that his daughter-in-law is married to him by his Allah directly without getting any permission from her parental concerns which is mentioned in Tafsir al-Jalalayn of 33:37
— the Prophet consummated his marriage with her without the customary permission from her legal guardian and gratified the Muslims with a feast of bread and meat —
Read the yellow marked part. It says seeing Zaynab undressed in her chamber, admiration for her entered the heart of Muhammad.
Zaynab was in her chamber, undressed, and admiration for her entered the heart of the Prophet
Did you read the red underlined words, After that happened she was made unattractive to the other man. Wow! seems like Allah is pleasing Muhammad to marry daughter-in-law for him.
Remember Aisha saying in https://sunnah.com/bukhari:5113
Aisha said, 'O Allah's Messenger (ï·º)! I do not see, but, that your Lord hurries in pleasing you.'
This is also mentioned in Imam Qurtubi's Tafsir of 33:37
The proposal is made by Zayd itself to Zaynab. Muhammad got no patience and he entered upon her without any formalities before Zaynab consult her Lord.
After this another verse in the same surah which is Quran 33:40
So, Zayd was one of the victim of the privilege given to Muhammad.