1 Corinthians 7:10-12

10 To those who are married I have a command, and it is not from me but from the Lord: a woman is not to separate herself from her husband

11 But if she does separate herself, she is to remain single or be reconciled with her husband. Also, a husband is not to leave his wife.

12 To the rest I say — I, not the Lord: if any brother has a wife who is not a believer, and she is satisfied to go on living with him, he should not leave her.