Once someone has gone as far as divorce and remarriage there is to be no looking back. No regrets, past bridges are to be burned. To remarry the former mate is a thing of disgust in God's eyes. Such a sin brings cursing to the nation. A woman was free to marry a third husband.
Divorce is neither mandatory nor encouraged, even for sexual indecency.
The Old Testament does not institute divorce, but rather tolerates and regulates it to protect against greater wrong. No one has a right, independent of Biblical reasons, to divorce his or her partner. Divorce should never be considered an option until every attempt at reconciliation has failed. The relatively liberal permission of divorce under the Mosaic Law was simply a stopgap measure. Christ nullified this measure.