The majority of Muslims agree on the authenticity of the hadiths reported by both al-Bukhari and Muslim. This commenced in the first era of Islam, especially after the golden era of tadwin (compiling and writing down the hadiths) in the third and fourth centuries after Hijrah. They considered their two Sahihs the most reliable and authenticated sources of hadith.
Though having confidence in their authenticity, Muslim scholars pursue a scientific methodology and scrupulous verification when quoting them. It is reported that some Hadith scholars had criticized a few sahih or sound hadiths. Others, moreover, differed among themselves if certain hadiths mentioned in the two Sahihs adequately met the conditions stipulated by al-Bukhari and Muslim. Their discussion, however, did not reach the level of weakening the hadiths reported therein.

In this regard, Sheikh Muhammad Nur Abdullah states the following:

1. It is an established fact that hadith was written and recorded during the time of Prophet Muhammad (peace and blessings be upon him). At the time of the great caliphs, they used to have collections of hadith. `Abdullah Ibn `Abbas, Abu Hurairah and other companions who lived till that time used to reference of hadith, and other companions would ask them about the authenticity of hadiths and each of them used to say, “let me look in my book.” That refers to certain collection at that time.

2. The four caliphs were extremely busy with other state affairs, and they did not need a collection of hadith in one volume since the senior companions were there.

3. As for contradiction between the Qur’an and hadith, there is no contradiction between the Qur’an and any AUTHENTIC hadith in al-Bukhari or others. It is an established fact that the hadith is given a separate authority of establishing new rules in Islam.

As for imam Al-Bukhari, it is not correct that he collected the hadith 300 after the companions. It is known that he collected the hadith from scholars who preceded him, like Imam Malik who saw and met some righteous successors of the Prophet’s companions. It is known that Imam Malik, who was before Al-Bukhari, was the first to compile the hadith in a book.

Concerning the personal issues regarding the Prophet’s life with his wives, the Prophet (peace and blessings be upon him) is a role model and an exemplary to us. Even his private life should be open to the Ummah to learn. Even the private issues of intimacy and the like should be taught to other people so they can know the halal and haram regarding this relationship.

As regards the love relationship during a woman’s period, it is prohibited to engage in actual intercourse, but it is allowed to engage in other things such as kissing, hugging, etc. That is why `Aishah related that story about Prophet Muhammad (peace and blessings be upon him) to teach the Ummah that they cannot have sexual intercourse during that period, but they are allowed to do anything else.

Finally I would recommend reading these two books of hadith by Dr. M. Moustafa al-athami: Studies in Early Hadith Literature and Methodology of Hadith as they can help clear misconceptions.