There's this Muslim girl I love so much. While I was dating her, her parents found out and gave in her marriage to her cousin, who lives in another country. I don't know what to do now because we still love each other so much. She has accepted Jesus as Lord of her life. I helped her in every possible way to understand the Bible and with the help of God, the love of Christ has grown in her. Please, I need advice on what to do before the marriage is consummated. She said she won't do it if he comes back but I'm not sure she can stand the challenges. I need advice before it's too late. I don't want her to marry a family member. She's now in Christ and such acts are against the Law.
First, there is no law against a person marrying cousins in the Bible.
Second, if she is already married, there is nothing you can do. If she is engaged to be married and she is willing to break the engagement, then you could marry her, but since it will be against her parents' wishes, she will be breaking all ties with her family. Such a separation may be more than she can handle. Essentially you are going to find your in-laws to be your enemies.
Third, accepting Jesus as Lord does not make a person a Christian. See: How to Become a Christian.
What am I suppose to do now? Without sex can the couple be completely joined by God? They have never had sex and never made any vows or agreement to marry each other. It was just the parents who did everything on their behalf.
A marriage is made by a covenant. "She is your companion and your wife by covenant" (Malachi 2:14). Until marriage vows are exchanged by the couple, there is no marriage. Sex does not create a marriage.
Again, it is up to you to decide whether you want to ask her to marry you and it is up to her to decide if she would rather run off to marry you against her parents' wishes or not. If the two of you decide to get married, realize that in doing so you will be making her family your enemies. She will especially have a difficult time and it would require strong character on her part to commit herself to you.