Generally a man should not have sexual relations with any woman other than his wife. According to Vedic principles, the wife of another man is considered ones mother, and sexual relations are strictly forbidden with ones mother, sister and daughter. If one indulges in illicit sexual relations with another mans wife, that activity is considered identical with having sex with ones mother. This act is most sinful. The same principle holds for a woman also; if she enjoys sex with a man other than her husband, the act is tantamount to having sexual relations with her father or son. Illicit sex life is always forbidden, and any man or woman who indulges in it is punished in the manner described in this verse.