A man divorced his wife thrice (by expressing his decision to divorce her thrice), then she married another man who also divorced her. The Prophet ﷺ was asked if she could legally marry the first husband (or not). The Prophet ﷺ replied, "No, she cannot marry the first husband unless the second husband consummates his marriage with her, just as the first husband had done."  

أَنَّ رَجُلاً طَلَّقَ امْرَأَتَهُ ثَلاَثًا فَتَزَوَّجَتْ فَطَلَّقَ فَسُئِلَ النَّبِيُّ ﷺ أَتَحِلُّ لِلأَوَّلِ قَالَ لاَ حَتَّى يَذُوقَ عُسَيْلَتَهَا كَمَا ذَاقَ الأَوَّلُ  

"Is she permissible for the first (husband to remarry her)?" He said: "No, not until he tastes her sweetness as the first tasted her sweetness."  

أَنَّ رَجُلاً طَلَّقَ امْرَأَتَهُ ثَلاَثًا فَتَزَوَّجَتْ زَوْجًا فَطَلَّقَهَا قَبْلَ أَنْ يَمَسَّهَا فَسُئِلَ رَسُولُ اللَّهِ ﷺ أَتَحِلُّ لِلأَوَّلِ فَقَالَ لاَ حَتَّى يَذُوقَ عُسَيْلَتَهَا كَمَا ذَاقَ الأَوَّلُ