Does what transpired between the man and the woman—kissing and touching her vagina without penetration—constitute zina (unlawful sexual intercourse), knowing that he was unaware she was married, and their intention was to marry after her divorce?

Interactions between non-mahram men and women, including conversations and correspondence without a legitimate need, open doors to temptation and corruption. If the situation escalates to seclusion (khalwa) and direct physical contact, that is a clear disobedience and manifest sin. The Prophet, peace be upon him, called this the fornication of the eyes, ears, tongue, hands, and feet. This is referred to as metaphorical fornication, as stated in the hadith narrated by Abu Hurairah in Sahih Muslim.

There is also a severe warning against merely touching a non-mahram woman, as the Prophet, peace be upon him, said: "For one of you to be stabbed in the head with an iron needle is better for him than that he should touch a woman who is not lawful for him."

The sin intensifies and the calamity escalates by corrupting a woman against her husband, which is among the gravest prohibitions. Some scholars have even ruled that the marriage of a woman to the one who corrupted her against her husband is invalid.

Therefore, one must hasten to repent to Allah Almighty by abandoning the sin, regretting having committed it, and resolving never to return to it. One must also sever all ties with that woman. If you are not married, then hasten to marry a righteous woman, fear Allah Almighty, and beware lest the Quran be a proof against you.