Should a man be told of his wife’s immoral conduct?
Question

Someone found out that another man’s wife is committing zinaa. Does he have to tell her husband?
Praise be to Allah.We put this question to Shaykh ‘Abd-Allah ibn Jibreen, may Allah preserve him, who answered as follows:
If she persists and is admonished but does not repent, then in this case we think that it is obligatory to tell her husband lest “his bed be corrupted” (i.e., lest his honour is compromised and/or a child be born that is not his and thus the lineage is corrupted).
And Allah knows best.