1 Corinthians 7:10-12

Now I give this command for the married people. (The command is not from me; it is from the Lord.) A wife should not leave her husband. But if she does leave, she must not marry again, or she should make up with her husband. Also the husband should not divorce his wife. For all the others I say this (I am saying this, not the Lord): If a Christian man has a wife who is not a believer, and she is happy to live with him, he must not divorce her.