Is it permissible to distance oneself from a woman to whom one had promised marriage, after she filed for Khul’ (dissolution of marriage initiated by the wife) and before the ruling is issued, while fearing sin for breaking the promise?

A man's promise to marry a married woman is impermissible; it is a forbidden act of incitement (takhbib) and one of the most heinous sins. He must immediately cut off the relationship with her, repent to Allah, and close the door to temptation. He may marry her only if she divorces her husband and her waiting period ('iddah) has expired.