What is the ruling on a young man's conduct with his wife's mother, such as kissing, hugging and touching without intercourse? Does his wife become forbidden to him because of that? And are these acts a wrong against that woman's husband which repentance does not undo?

Enjoying one's mother-in-law is a grave abomination. However, Allah accepts sincere repentance, which entails abandoning the sin, regretting it, and resolving not to return to it, while maintaining discretion and avoiding public disclosure. This forbidden act does not, according to the preponderant scholarly view, render the wife unlawful. Directing passion towards the mother-in-law without penetration or kissing her with desire does not prohibit the wife, only intercourse does. It is not a condition for valid repentance to seek forgiveness from the husband of the woman with whom the illicit act occurred; rather, repentance to Allah and concealing one's sin and the woman's suffice.