Don't forget Matthew 5:31-32:- "It was said, 'Anyone who divorces is wife should give her a certificate of divorce' [Deuteronomy 24:1-4]. But I'm telling you that everyone who divorces his wife (except for a matter of fornication) makes her commit adultery; and anyone who marries a divorced woman commits adultery." So, even from 'Jesus' lips' we have an exception - ["fornication " = "illicit marriage"? Differing incest laws between Hebrews and Greeks? Whatever.] And then came Paul, and later the 'Petrine Privilege'. In the West today almost half of first marriages turn out to be a mistake; a majority of second marriages work out fine.