When is a divorce final? If a man or a woman discontinues the marriage, is the divorce final in God's eyes? Or is it not final until the courts decide the outcome?
God didn't establish details for what constitutes a marriage beyond the fact that a covenant creates it (Malachi 2:14). The terms for the covenant or the accompanying ceremonies are not specified. We find a variety of practices with people getting married in one day (Isaac and Rebekah) to a wedding feast that lasts a week (Jacob and Leah). The variation doesn't make the marriage any less or more real. In such a case, the laws of the land and the customs of the people dictate the specifics, so long as a covenant takes place.
Similarly, while "divorce" is mentioned (Matthew 5:32; 19:9; Mark 10:11-12; Luke 16:18; I Corinthians 7:10-11) exactly how it is to be accomplished is not specified. So once again, it is the laws of the land and the customs of the people that set the details.
"Let every soul be subject to the governing authorities. For there is no authority except from God, and the authorities that exist are appointed by God. Therefore whoever resists the authority resists the ordinance of God, and those who resist will bring judgment on themselves" (Romans 13:1-2).
A couple is married until the conditions are met in which society no longer considers them as husband and wife. In the United States, covenants, like other contracts, have to be ended by court decree when the terms are not met. This provides an unbiased examination of what happened and whether what happened rises to the level of releasing the parties from their agreement. Unfortunately, we lost a lot of that in recent decades with the "no-fault" divorce laws. At least most states still retain a requirement of a waiting period to make sure the couple is certain they want the divorce and have a chance to reconcile.