حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عَبْدُ السَّلاَمِ بْنُ حَرْبٍ، عَنْ هِشَامِ بْنِ حَسَّانَ، عَنِ الْحَسَنِ، عَنْ سَلَمَةَ بْنِ الْمُحَبِّقِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم رُفِعَ إِلَيْهِ رَجُلٌ وَطِئَ جَارِيَةَ امْرَأَتِهِ فَلَمْ يَحُدَّهُ ‏.‏

It was narrated from Salamah bin Muhabbiq that: the case of a man who had intercourse with the slave woman of his wife was referred to the Messenger of Allah (PBUH), and he did not stipulate any legal punishment for him. Translation Not Available

Book Ref: Sunan Ibn Majah Book 20 Hadith 2552
Web Ref:  Sunan Ibn Majah Vol 3 Book 20 Hadith 2552