Sahih Muslim 1471 l
Ayyub reported a hadith like this with the same chain of narrators and he said:
Umar (Allah be pleased with him) asked Allah's Apostle (ﷺ) about it and he commanded him that he should take her back until she is divorced in the state of purity without having a sexual intercourse with her, and said: Divorce her in the beginning of her 'Idda or her 'Idda commences.
وَحَدَّثَنَا عَبْدُ الْوَارِثِ بْنُ عَبْدِ الصَّمَدِ، حَدَّثَنِي أَبِي، عَنْ جَدِّي، عَنْ أَيُّوبَ، بِهَذَا الإِسْنَادِ وَقَالَ فِي الْحَدِيثِ فَسَأَلَ عُمَرُ النَّبِيَّ صلى الله عليه وسلم عَنْ ذَلِكَ فَأَمَرَهُ أَنْ يُرَاجِعَهَا حَتَّى يُطَلِّقَهَا طَاهِرًا مِنْ غَيْرِ جِمَاعٍ وَقَالَ ‏
"‏ يُطَلِّقُهَا فِي قُبُلِ عِدَّتِهَا ‏"‏ ‏.‏