Read your article and agree what you wrote down concerning Jesus’ teachings of the exceptive clause about fornication, which was addressing the Jewish custom. As for Christians, though, it will best to divorce during the betrothal or engagement stage…
In western, contemporary society, civil laws governing marriage do not include an engagement or a betrothal in the legal proceedings of a wedding. Biblical Judaism overshadowed cultural, religious and civil circumstances, and it lumped together the engagement or betrothal—a legal contract—with the officiation of the wedding.
The Bible does not designate a wedding as a religious activity other than that a man and a woman may marry to avoid immorality (1 Corinthians 7:2, 36). Therefore, people must address the laws of the land under which they live (Romans 13:1-7) respecting the legal proceedings of obtaining and defining a marriage. Whatever legal procedure required in a nation to constitute a marriage is obligatory upon couples intending to wed (as long as man’s laws do not conflict with the laws of God, Acts 5:29, e.g., so-called “homosexual marriages”).
However, once a marriage has occurred, Deity requires that the marriage continue, except that a separation or divorce from marriage may occur due to fornication (Matthew 5:32) or because of desertion (1 Corinthians 7:12-15). Jesus Christ set a precedent for the Christian or Gospel Age regarding divorce from a marriage, stipulating that only the innocent party to fornication may remarry (Matthew 19:9).
New Testament teachings concerning marriage, divorce and remarriage are not confined to consideration of biblical Judaism (e.g., the Gospel of Matthew). The Gospel account by Mark likewise presents our Lord’s marriage instructions to non-Jews—Romans (Mark 10:11-12). The Gospel according to Luke also represents the teaching of Jesus about marriage, divorce and remarriage to a universal, international readership (Luke 16:18). Of course, New Testament epistles also contain marriage instructions (e.g., Ephesians, 1 Corinthians).
In conclusion, in nations with which I am familiar, an engagement or a betrothal to be married is not part of a legal marriage. Therefore, an engagement or a betrothal in those countries may be terminated without violating New Testament biblical instruction about marriage, divorce and remarriage. That scenario may not be true in all contemporary nations, and some countries may have laws comparable to legal requirements governed by first century Judaism. (Though Palestine was under Roman rule in the first century, to an extent, Jews were permitted to govern themselves.)