Is it permissible to report a man who commits adultery with married women with their consent, and refuses to stop, knowing that my husband is a close friend of this man?

Adultery is forbidden and is a major sin. The sin is compounded if the adulterer commits adultery with married women, due to the transgression against the husband's rights and the violation of his honor. For the adulterer to inform others about his deed is another transgression; rather, he must repent and conceal his sin. As for anyone who becomes aware of his affair, he must denounce it, remind him of God, and threaten to inform those who can deter him. If he does not desist, then the responsible authorities should be informed to restrain him.