1 Corinthians 7:12-13

12To all you other people, I say this. (This is what I think. The Lord has not spoken about it.) A Christian man may have a wife who does not believe in Christ. If she agrees to continue living with him, then he should not send her away.

13Also, a Christian woman may have a husband who does not believe in Christ. If he agrees to continue living with her, then she should not leave him.