This is not so much about divorcing wives as it is about repairing the divorce from God. So the proposal for discipline: when you have sinned, bring the matter to the Word of God, the standard of God's Word. And to those ministers and officers who are to administer the Word of God, search the Scriptures to find the solution. That is clearly what they are trying to do here in Ezra 10:3:
let it be done according to the Law.It is not just what we think should be accomplished here. If it was up to us, we would either be too indulgent and allow the practice to go on, or we would be too strict, maybe even kill the people.1
3 Therefore let us make a covenant with our God to put away all these wives and their children, according to the counsel of my lord and of those who tremble at the commandment of our God, and let it be done according to the Law.