Abu Saeed Al-khudri reported the Messenger of Allah ﷺ as saying: The most serious breach of trust in Allah’s sight is that a man who has intercourse with his wife, and she with him, spreads her secret.
Related hadith on this topic
Explanation & Benefits
Shaykh Umar Farooq Saeedi
Benefits and Issues:
Allah, the Mighty and Majestic, has made husband and wife as garments for one another, so to disclose each other's secrets before others is a very reprehensible act.
Except in the case where, due to some Shar‘i necessity, one is required to mention something before a judge (qadi) or the like.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 4870
Shaykh Maulana Abdul Aziz Alvi
Hadith Commentary: Benefits and Issues: A husband and wife have intercourse with each other in seclusion from people, which is an indication that this is a concealed act, the disclosure of which is not appropriate. Therefore, if a husband and wife describe or depict this act and its details before others, it is a betrayal of trust and the disclosure of a hidden secret, which is an extremely reprehensible act and one that is liable to accountability.
Source: Tuhfat al-Muslim: Commentary on Sahih Muslim, Page: 3543