NET
15 But if the unbeliever wants a divorce, let it take place. In these circumstances the brother or sister is not bound. God has called you in peace.
Darby
15 But if the unbeliever go away, let them go away; a brother or a sister is not bound in such [cases], but God has called us in peace.
KJV
15 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.