1 Corinthians 7:10-11, 15

And unto the married I command, yet not I, but the Lord, Let not the wife depart from her husband: but and if she depart, let her remain unmarried, or be reconciled to her husband: and let not the husband put away his wife.

But if the unbelieving depart, let him depart. A brother or a sister is not under bondage in such cases: but God hath called us to peace.