All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
Before we answer your question, we would like to highlight two points:
Firstly, we have received a number of questions from you about such misconceptions. You should know that it is not wise to preoccupy yourself with following such misconceptions; undue exposure to misconceptions and false claims about Islam incurs danger and fitnah (tribulation) upon the person except those whom Allaah safeguarded. It is feared that these misconceptions would dwell in the heart of the Muslim and the mind may not fully comprehend the refutation.
Secondly, it is important to refute such misconceptions and convince their advocates of their wrong perception; however, some may adamantly object even if the refutation is clarified to them. In this case, one should not bother trying to convince such people in the first place. Allaah, The Exalted, says (what means): {And even if We had sent down to you [O Muhammad] a written scripture on a page and they touched it with their hands, the disbelievers would say, "This is not but obvious magic."} [Quran 6:7]
Allaah, The Exalted, also says (what means): {Indeed, those upon whom the word of your Lord has come into effect will not believe, even if every sign should come to them, until they see the painful punishment.} [Quran 10:96-97]
This hadeeth is authentic and is even held in the highest level of authenticity as it has been reported by both Al-Bukhari and Muslim . An-Nawawi said, "The authentic ahaadeeth are of different categories; the highest level of authenticity is for those narrated by both Al-Bukhari and Muslim..." [At-Taqreeb]
The ahaadeeth cited in Saheeh Al-Bukhari and Saheeh Muslim are collectively accepted by Muslims as the most reliable. An-Nawawi said, "Muslim scholars agreed that Saheeh Al-Bukhari and Saheeh Muslim are the most authentic books after the Noble Quran, and they are collectively accepted by the Muslim broader community."
There versions of this hadeeth were different with regards to the number mentioned in them. Al-Haafith Ibn Hajar cited all these versions and reconciled between them in his book Fat-h AL-Baari, saying:
"In brief, the different versions mention the number (of the wives of Prophet Sulaymaan [Solomon] ) as sixty, seventy, ninety, ninety-nine, and one hundred. They can be reconciled in the sense that the wives were sixty free women and the rest were concubines or vice versa. Seventy denotes the large number as a form of exaggeration. Ninety and one hundred; they were less than one hundred and more than ninety. Those who say that they were ninety wives discarded the fraction and those who say they were one hundred rounded up the number."
Indeed, this is a rational interpretation that appeals to the sound mind. If such people find it not convincing, no extra effort should be exerted in trying to convince them.
It is unbecoming of the Prophet to contradict himself; he is deemed far above such a shortcoming. His words are part of the divine revelation; Allaah, The Exalted, says (what means): {Nor does he speak from [his own] inclination It is not but a revelation revealed.} [Quran 53:3-4]
As for their allegation that the content of this hadeeth is unreasonable and their questioning of the physical ability of a man to have intercourse with this great number of women in one night, it can be refuted by the fact that it is not rationally impossible because Allaah, Who bestowed the physical ability to have intercourse once or twice in one night upon man may grant him greater ability and power to have more intercourse in one night as well. Moreover, even if this is unreasonable as far as laymen are concerned, it is not unlikely with regards to the Prophets of Allaah, whom He endowed with great physical strength that has never been given to others.
Anas ibn Maalik said, "The Prophet used to visit all his wives in a round, during the day or night, and they were eleven in number." I asked Anas, "Had the Prophet the strength for it?" Anas replied, "We used to say that the Prophet was given the strength of thirty (men)." [Al-Bukhari, Muslim and others]
Jaami’ Al-Usool reads, "Prophets of Allaah were endowed with greater sexual potency and virility; when the heart is filled with light (of faith), it overflows into the veins, fueling physical strength and sexual potency and virility, which are enhanced by the piety of the heart and mind; this is the genuine source of strength."
Allaah knows best.