I am married with a woman who was brought up in a catholic environment and I am endeavouring to turn her into a Muslim, Allaah willing. The problem is that before I married her, she used to live with a person and after we married for a while, that person claimed that he has a paper which proves that he is married to her in Morocco in 1989. However, my wife did not know anything about this and did not sign any paper, and she was not present nor was her guardian. Since that time, I am embarrassed and troubled fearing that my marriage to her is void and that I am in sin, taking into account that I married her with the presence of her guardian, two trustworthy witnesses and the Imaam of the mosque. Is my marriage to her valid?

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. We ask Allaah to exalt his mention as well as that of his family and all his companions.

Your marriage, dear brother, is correct if this woman did not have a husband because if she was married, then your marriage to her is void, as it is not permissible to marry a person who is already married. A woman can only be married once at a time. So if this man claims that he is the husband of this woman while your Christian wife denies it, then it is her statement that should be taken into consideration unless the man provides evidence that he is married to her and did not divorce her, and it is only the court which could rule about this. 

Allaah Knows best.