How can a woman overcome her feelings of guilt after sincere repentance from the sin of adultery she committed while married, especially as she suffers from self-dissatisfaction and fears deceiving her husband, and how can she restore her heart's tranquility and the stability of her life?

There is no doubt that your seclusion with this foreign man and your commission of adultery are among the most heinous of prohibitions. However, we praise Allah that He has bestowed upon you repentance. Know that among its requisites are severing ties with this young man, regretting what has passed, and resolving never to return to such a sin. If your repentance is of this nature, then rejoice in the bounty of Allah Almighty, as He has promised those who repent that He will accept their repentance, no matter how great their sins. What strengthens this repentance is an abundance of good deeds, constantly being mindful of Allah Almighty in secret and in public, and accompanying righteous people. You are not permitted to disclose this sin to anyone; rather, you must conceal yourself with the veil of Allah. This act, although heinous, should not spoil your relationship with your husband, and it does not affect the validity of your marriage according to all scholars.