Firstly, it would be helpful for us to look at the Bible’s definitions of what is a Christian and what is a Muslim.

A Christian is someone who is saved by the death and resurrection of Christ and who follows Jesus as Lord. We can see this in the book of Romans in the New Testament.

That if you confess with your mouth, “Jesus is Lord,” and believe in your heart that God raised him from the dead, you will be saved.
Romans 10:9

Calling Jesus Lord means accepting the forgiveness he brings and acknowledging him as the master of our lives. In the book of Matthew, verse 7:21, it says that

Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but only he who does the will of my Father who is in heaven.
Matt 7:21

So you see a Christian will always try their hardest to obey God, even though they sometimes may fail, they will not willfully want to disobey God. If they do, there is forgiveness in Jesus.

What is a Muslim? Although the Muslim and Christian faiths share a lot of their scriptures in common, their beliefs are fundamentally different at points where it counts. While a Muslim belives Jesus to be a prophet, they do not believe that he is God nor that he rose from the dead. This is why the Muslim belief and the Christian belief can never be compatible, because they believe the opposite things about the most crucial person in the Christian religion, Jesus. (see quote from Romans 10:9 above). This does not mean people who follow Jesus and those who follow Islam cannot live in peace together. Christians are called to leave peaceably with others. But their faiths are very different.

In the book of John it says about Jesus

Whoever believes in him is not condemned, but whoever does not believe stands condemned already because he has not believed in the name of God’s one and only Son.
John 3:18

The Bible makes it clear that if a woman has the freedom to choose her own husband, (which in those times only happens in the rare circumstances that the woman becomes widowed - otherwise marriages were always arranged), they should marry a Christian.

A woman is bound to her husband as long as he lives. But if her husband dies, she is free to marry anyone she wishes, but he must belong to the Lord.
1 Cor 7:39

This is God’s command, and it is also wise, because God tells us that the marriage relationship is one that should help us to grow in godliness, not hinder us. In fact, husbands are commanded to love their wives and help to make her holy. (See Ephesians 5:25-33) It would be impossible for someone who doesn't know Jesus to help his wife do this.

If you are a Christian yourself, I encourage you to think more deeply about your relationship with God. Are you someone who follows Jesus, or do you just call him Lord without doing God’s will in your life? Are you sure that you will have eternal life when you die? If you want to think deeper about these questions, please have a look around this website that tells you more about Jesus, or maybe pick up the Bible and read about Jesus in the New Testament, and consider his claims as the master of our lives?