(Al-Ahsaab) 33 : 52
لَا يَحِلُّ لَكَ النِّسَاءُ مِنْ بَعْدُ وَلَا أَنْ تَبَدَّلَ بِهِنَّ مِنْ أَزْوَاجٍ وَلَوْ أَعْجَبَكَ حُسْنُهُنَّ إِلَّا مَا مَلَكَتْ يَمِينُكَ ۗ وَكَانَ اللَّهُ عَلَىٰ كُلِّ شَيْءٍ رَقِيبًا
It is not lawful for you to marry any woman after that, or change any of your wives with another woman, even though their character may attract you greatly, except your right-hand possessed woman, and Allah is watching upon everything.