Question - since God instituted the state of marriage, then did He also join couples who are nonbelievers?
Answer:
It appears that the "joining" by God is a reference to His institution of marriage in general. When Jesus said that, He was answering a question from unsaved Pharisees, so I don't think He was limiting His statement to people in the body of Christ on our side of the cross. It also appears from the admonitions given in 1 Cor. 7 to a believer to not put away or leave an unsaved spouse, God considers an unequally yoked couple to be joined or yoked in a union that is not to be broken, except by the deliberate move of the unsaved person
