Did Prophet (peace and blessing be upon him) ever in his life look on the private parts of his wives? This Hadith is narrated from Aisha (May Allah be pleased with her) that he (peace and blessing be upon him) never looked at my private parts and I never looked at his private parts? Why did he never do that? Was that for modesty and shyness? Is this Hadith true? Because there is also narrated a Hadith where Aisha (May Allah be pleased with her) narrated that me an Prophet (peace and blessing be upon him) bathed together in a single pot of water? Was they not naked in front of each other on this event? Is it Haram for every Muslim husband and wife to look at each other's private parts?

Praise be to Allah, the Lord of the World; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
The Hadith reported by Ahmad from Aisha () that she said: "I never looked at the Prophet's private parts and never saw them". This Hadith is weak.
It is reported by Al-Bukhari and Muslim from a sound Hadith that the Prophet used to make Ghusl (ceremonial washing) with some of his wives from the same receptacle. Aisha () said: "I used to make Ghusl, me and the Prophet using the same receptacle". In another narration she said: "Our hands would cross in that receptacle and we would touch each other".
The scholars use this Hadith as an evidence that it is lawful for both spouses to look at each other's private parts.
Ibn Hajar (a famous Muslim scholar) said: 'This evidence is supported by what Ibn Hibban reported from Ata'a who said that he asked Aisha () about the spouses looking at each other's private parts and she replied by the Hadith cited above'. Since touching and even having sexual intercourse with the wife is permissible, then looking at her and vice versa is also permissible.
Al Tirmizi also reported from Bahz Ibn Hakim who said: "I asked the Prophet (Peace and blessing be upon him) from whom should we conceal our private parts and to whom can we show them? He replied: "Conceal your private parts except from your wife and your slave woman". [Al-Tirmizi]
So, if it were prohibited for the husbands to look at their wives private parts or vice verse, the Prophet would have said so. It is lawful in Shariah for the spouses to look at each others private parts.
Allah knows best.