A man from the Ansar came to the Messenger of Allah ﷺ and asked, "Messenger of Allah, what do you say about a man who finds another man with his wife? Should he kill him, or what should he do?"Then Allah revealed concerning his case what is mentioned in the Quran about the Mutalaineen. The Prophet ﷺ said, "Allah has issued His ruling concerning you and your wife."So they performed the mutual imprecation in the mosque, and I was present. When they had finished, the man said, "I would be lying against her, Messenger of Allah, if I kept her," and he divorced her three times before the Messenger of Allah ﷺ could instruct him to do so, once they had completed the imprecation. He thus separated from her in the presence of the Prophet ﷺ, who said, "That is the separation between every couple who perform mutual imprecation."
أن رجلا من الأنصار جاء إلى رسول الله ﷺ فقال: يا رسول الله! أرأيت رجلا وجد مع امرأته رجلا، أيقتله أم كيف يفعل؟ فأنزل الله في شأنه ما ذكر في القرآن من أمر المتلاعنين فقال النبي ﷺ: قد قضى الله فيك وفي امرأتك قال: فتلاعنا في المسجد وأنا شاهد. فلما فرغا قال: كذبت عليها يا رسول الله إن أمسكتها، فطلقها ثلاثا قبل أن يأمره رسول الله ﷺ حين فرغا من التلاعن، ففارقها عند النبي ﷺ فقال: ذاك تفريق بين كل متلاعنين
Bukhari related it in the book of divorce (5309), and Muslim in the book of mutual imprecation (1492, 3), both through Abdul-Razzaq. Ibn Jurayj informed us, he said, Ibn Shihab informed me about mutual imprecation and about the established practice concerning it, from the hadith of Sahl bin Saad, and he narrated it.The wording given here is Bukhari's. The unnamed man from the Ansar is Uwaymir Ajlani. His statement, "That is a separation between every pair who engage in mutual imprecation," indicates that a couple who have engaged in mutual imprecation can never come together again.