Qur'an 33:52

لَّا يَحِلُّ لَكَ ٱلنِّسَآءُ مِنۢ بَعْدُ وَلَآ أَن تَبَدَّلَ بِهِنَّ مِنْ أَزْوَٰجٍ وَلَوْ أَعْجَبَكَ حُسْنُهُنَّ إِلَّا مَا مَلَكَتْ يَمِينُكَ ۗ وَكَانَ ٱللَّهُ عَلَىٰ كُلِّ شَىْءٍ رَّقِيبًا

It is not allowed thee to take (other) women henceforth, nor that thou shouldst change them for other wives even though their beauty pleased thee, save those whom thy right hand possesseth. And Allah is ever Watcher over all things.