It is one of the greatest calamities that can beset a marriage. Either the husband or the wife betrays Allah and the trust of their marriage partner and engages in adultery. It more often than not leads to the end of the marriage and the ruin of the family. In traditional societies, this is more likely to be the case when the woman has committed adultery.
Some people believe that adultery requires the dissolusion of the marriage as a religious obligation. This is not true. The choice to forgive and try to save the marriage remains with the other spouse. In many cases, the marriage can be saved.
If a man or woman commits adultery, it does not affect the lawfulness or validity of the marriage from an Islamic legal perspective. The man who committed adultery remains the lawful husband of his wife. The woman who committed adultery remains the lawful wife of her husband. It is not obligatory for them to get divorced.
The proof for this is that the Prophet (peace be upon him) did not seek out the married woman whom Mâ`iz committed fornication with. He did not inquire after her husband and command him to divorce her. All he said was: “O Unays, go to that man’s wife, and if she confesses, then have her stoned.” [Sahîh al-Bukhârî (6633) and Sahîh Muslim (1698)]
We can see that the Prophet (peace be upon him) did not instruct that the husband must divorce his wife or that she had become unlawful to him.
The children born of a woman who committed adultery are attributed to the woman’s husband according to Islamic Law. The integrity and continuity of the family is in this way preserved, as well as the legitimacy of the child and its place in its parents' home.
Adultery has no legal effect in such matters, because what is unlawful in Islam is regarded as nonexistent for such purposes. The evidence for this is that the Prophet (peace be upon him) said: “The child belongs to the (marriage) bed, and the adulterer is stoned.” [Sahîh al-Bukhârî (2053) and Sahîh Muslim (1457)]
Therefore, the child is attributed to the woman’s husband. Any paternity claim of the man with whom she committed adultery is of no consequence in contesting the husband’s paternity.
A repentant adulterer can still be a good husband or wife. If a man claims he has sincerely repented for his sin, his wife can keep him as her husband. Likewise, if the woman claims that she has repented for her mistake, then her husband has every right to keep her as his wife. Allah says about those who repent: “Say: O my Servants who have transgressed against their souls! Despair not of the Mercy of Allah: for Allah forgives all sins: for He is Oft-Forgiving, Most Merciful.” [Sûrah al-Zumar: 53]
Allah also says: “And whoever repents and does good has truly turned to Allah with true repentance.” [Sûrah al-Furqân: 71]
The Prophet (peace be upon him) said: “Allah accepts the repentance of His servant as long as he has not reached the throes of death.” [Sunan al-Tirmidhî (3537) and Sunan Ibn Mâjah (4253)]
He also said: “Allah stretches forth his hand at night to those who had sinned during the day, and he stretches forth His hand during the day for those who had sinned during the night.” [Sahîh Muslim (2759)]
The spouse will be able to tell if the adulterous husband or wife is sincere in repentance by observing the behavior after repentance. The truly repentant person who has returned to the obedience of Allah will tend to exhibit more piety . Signs of this include observing prayers and fasts, modesty in dress, engaging in voluntary worship, and her feeling remorse for the mistake. These are among the signs that the person has truly repented to the Lord.
Moreover, the husband and wife are free to engage in intimacy after coming to know that the other spouse has committed adultery. There is no sin in this, and no prescribed waiting period when the adulterer is the woman. The reason for this is that the default ruling in Islamic Law is that a wife and husband are lawful for each other. Allah says: “Your wives are a tilth for you, so go into your tilth as you will.” [Sûrah al-Baqarah: 223]
However, if a spouse is persistent in adultery, exhibits a wanton attitude, and is unrepentant; then that person should not be kept as a marriage partner. Allah says: “The adulterer shall not marry save an adulteress or an idolatress, and the adulteress none shall marry save an adulterer or an idolater. All that is forbidden to the believers.” [Sûrah al-Nûr: 3]
And Allah knows best.