﴿ إِلَّا عَلَىٰٓ أَزْوَٰجِهِمْ أَوْ مَا مَلَكَتْ أَيْمَٰنُهُمْ فَإِنَّهُمْ غَيْرُ مَلُومِينَ ﴾

“[not giving way to their desires] with any but their spouses - that is, those whom they rightfully possess [through wedlock] -: for then, behold, they are free of all blame,”

Please check ayah 70:35 for complete tafsir.