1 Corinthians 7:11-13

But if she does, then she should either remain unmarried or reconcile with her husband. And a husband must not divorce his wife. To the rest I say, which is not a saying of the Lord, if a brother has an unbelieving wife and she is content to live with him, he should not divorce her. And if a woman has a husband who is not a believer and he is content to live with her, she should not divorce him.