Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Thanks for your question, which really emanates from a thoughtful and God-fearing heart. May Allah forgive us all our sins, and may He guide us all to the best in this world and reward us all generously in the Hereafter.
Dear sister, you should first repent to Allah sincerely keeping in mind that the door of repentance is wide open. However, your repentance should be sincere so as to get your sins forgiven. Indeed, it is a blessing from Allah that your husband has given you a second chance to live together after sullying the marital bed.
Responding to the question, Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
Adultery is indeed an abominable act which we must stay away from, and if we ever fall into it, then we must sincerely repent and make amends in order to be worthy of Allah’s forgiveness. Allah says, “Do not even go near fornication for it is an abomination and evil life-style.” (Al-Israa’ 17:32)
Repentance, however, must never be confused with simply saying I ask forgiveness of Allah; rather it requires turning your whole life around so that you shun the sin and run away from it as you would run away from a fire or predatory beasts. Therefore, scholars have stipulated three essential conditions of true repentance. They are namely, first and foremost, to experience true feeling of remorse and contrition for one’s behavior so that one resents it at heart; second, to refrain from the sin as well as all the avenues and circumstances that led to it in the first place; therefore, it is essential that we cut off all relations, acquaintances, and friendships that led or would potentially lead to the same, third, to make firm resolution in one’s mind never to do it again.
Thus, you are required to make amends for your sin by engaging in whatever good works you can possibly do to expiate for the same. Good deeds to consider are: giving charity, asking lots of forgiveness, and dhikr, offering optional prayers and fasts, and so on. You are advised to consistently pray to Allah to keep you chaste and pure; in this regard you can use the following supplication on a regular basis:
Allaahumma tahhir qalbee wa ahsin farjee
(O Allah, cleanse my heart (of all taints of fornication) and help me remain chaste and pure.)
Rabbi qinee sharra sam’ee; rabbi qinee sharra basaree, rabbi qinee sharra lisaanee; rabbi qinee sharra maniyyee
(My Lord, protect me against the evils of my hearing; Lord, protect me against the evils of my eyes; Lord, protect me against the evils of my tongue; Lord, protect me against the evils of my private parts.)
It is important that you take the above points seriously, for despite the fact that your husband has forgiven you, you still cannot expect to be saved from the terrible chastisements of Allah except through sincere repentance.
Now coming to the second point mentioned in your question, let me state: if your husband has allowed you a second chance, you should consider it a blessing from Allah and consider it as a challenge for you to keep his trust and never sully the marital bed again. Take all the steps necessary to make your marriage stronger and stronger, regardless of whatever happened in the past, for Islam teaches us to look to the future. In other words, as the Prophet (peace and blessings be upon him) is reported to have said, “One who has repented of a sin is like someone who has never sinned at all!” (Ibn Majah)
Finally, once you and your husband have reconciled to the fact and that you have pledged together sincerely to make it work after you have assured him of sincere repentance and change in your lifestyle, there is no need for both of you to renew the nikah. Marriage is not automatically broken by the act you have committed. Therefore, I urge you to come near to Allah and beg His pardon and forgiveness and dedicate yourself to a life of God-consciousness, purity, and virtue.
May Allah save us all from the evil inclinations inherent in our nature and may He cover our shame on a Day when both the hidden and open secrets will be revealed for all to see.
Allah Almighty knows best.