Husband took as second wife one who committed adultery with him
13-3-2004 | IslamWeb
Question:
I am a sister in need of help. My husband had commit adultery (Zina) with a woman who was married at the time. She left her husband to marry my husband. So he married her without my knowledge. I found out about it a couple of months later. I was told that I have to accept his marriage to her, that it is his right in Islam. Should I accept this marriage? Is his marriage to her valid?
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad 
is His slave and Messenger.
It is not permissible for a person to accuse a spouse or any other person of Zina (fornication or adultery) unless this is proven with evidence or that he confesses to it. Therefore, if it is proven that your husband had committed Zina, then he had committed a grave major sin and he is obliged to sincerely repent to Allaah. Allaah Says (what means): {And do not approach unlawful sexual intercourse. Indeed, it is ever an immorality and is evil as a way.} [Quran 17:32]
Allaah also Says (what means): {And those who do not invoke with Allaah another deity or kill the soul which Allaah has forbidden [to be killed], except by right, and do not commit unlawful sexual intercourse. And whoever should do that will meet a penalty. Multiplied for him is the punishment on the Day of Resurrection, and he will abide therein humiliated -Except for those who repent, believe and do righteous work. For them Allaah will replace their evil deeds with good. And ever is Allaah Forgiving and Merciful.}[25:68-70]
The sin is even more repulsive and abominable because he committed Zina with a married woman, and so, he violated her honour and that of her husband, and he destroyed the family of this husband and his bed, and spoilt his wife until he divorced her. The Prophet, sallallahu 'alaihi wa sallam, said: “The one who spoils the marital relationship of a woman with her husband is not one of us.”
As for marrying this woman after committing Zina with her, then if she is divorced by her husband, and her waiting period had expired, then the marriage is valid provided the man and the woman had sincerely repented from committing Zina; Allaah Says (what means): {The fornicator does not marry except a [female] fornicator or polytheist, and none marries her except a fornicator or a polytheist, and that [i.e. marriage to such persons] has been made unlawful to the believers.} [Quran 24:3]
The validity of the second marriage does not depend on the permission, knowledge or consent of the first wife.
Therefore, the jealousy of his first wife should not lead her to do what is forbidden, like objecting the ligitimacy of the marriage or disobeying her husband, or harming him or his second wife.
Allaah Knows best.