1 Corinthians 7:13-15

Also, if any woman has an unbelieving husband and he is willing to live with her, she must not divorce her husband. For the unbelieving husband is made holy by the wife, and the unbelieving wife is made holy by the husband. Otherwise your children would be unclean, but as it is they are holy. But if the unbeliever leaves, let him leave. A brother or a sister is not bound in such cases. God has called you to live in peace.