the case of a man who had intercourse with the slave woman of his wife was referred to the Messenger of Allah ﷺ, and he did not stipulate any legal punishment for him.
أَنَّ رَسُولَ اللَّهِ ﷺ رُفِعَ إِلَيْهِ رَجُلٌ وَطِئَ جَارِيَةَ امْرَأَتِهِ فَلَمْ يَحُدَّهُ