1 Corinthians 7:10-12
10 Now, I have a command for those who are married. Actually, it is not from me; it is what the Lord commanded. A wife should not leave her husband. 11 But if a wife does leave, she should remain single or get back together with her husband. And a husband should not divorce his wife.
12 The advice I have for the others is from me. The Lord did not give us any teaching about this. If you have a wife who is not a believer, you should not divorce her if she will continue to live with you.Read full chapter