Is there any verse of the Quran that states that discussing marital intimacy or seeking clarification about one's spouse should be avoided, whether in public or private settings?
Quranic verse are very clear in ordering the believers not to mention any thing which can hurt the feelings of a believer or might cause disrespect to him. Discussing marital intimacy or seeking clarification about one's spouse must not cause any harm or disrespect or annoying the spouse in any way.
Wassalam.