I said to Ibn Umar, "What about a man who accuses his wife of adultery?"He replied, "The Messenger of Allah ﷺ separated the two siblings of Banu Ajlan. He said, 'Allah knows that one of you is lying, so will either of you repent?' But they both refused. He repeated this to them three times, and they still refused, so he separated them."
حدثنا إسماعيل حدثنا أيوب
قلت لابن عمر رجل قذف امرأته فقال فرق رسول الله ﷺ بين أخوي بني العجلان وقال الله يعلم أن أحدكما كاذب فهل منكما تائب فأبيا فرددهما ثلاث مرات فأبيا ففرق بينهما
Its isnad is sahih. Abu Dawud (2:245) narrated it from Ahmad bin Hanbal with this same isnad. Munziri said, Bukhari, Muslim, and Nasai reported it in a similar manner. It has already appeared in abbreviated form from the hadith of Ibn Umar (398), and see also what has already appeared (2131, 4001, 4281) and what will come (4527, 4693, 4945).