Sunan Ibn Majah
2552
Daif+3

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 (ﷺ), and he did not stipulate any legal punishment for him

DaifAl-Albani
DaifMuhammad Fouad Abd al-Baqi