Narrated Sahl bin Sa'd (RA) concerning the story of the two (husband and wife) who invoked curses regarding one another:

When they finished invoking curses regarding one another the man said, "I shall have lied against her, O Allah's Messenger (ﷺ) , if I keep her (as a wife)." He, then, pronounced her divorce three times, even before Allah's Messenger (ﷺ) commanded him to do so. [Agreed upon].

وَعَنْ سَهْلِ بْنِ سَعْدٍ ‏-فِي قِصَّةِ اَلْمُتَلَاعِنَيْنِ‏- قَالَ: { فَلَمَّا فَرَغَا مِنْ تَلَاعُنِهِمَا قَالَ: كَذَبْتُ عَلَيْهَا يَا رَسُولَ اَللَّهِ! إِنْ أَمْسَكْتُهَا, فَطَلَّقَهَا ثَلَاثًا قَبْلَ أَنْ يَأْمُرَهُ رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-} مُتَّفَقٌ عَلَيْهِ .‏ [1]‏ .‏