I've never seen anyone suggest this, but it's the painfully obvious solution. Most people get divorced so that they can remarry. If they couldn't remarry, then divorces would become something only for people who are just really miserable and want a clear separation of goods and whatnot.

Since divorce rates increase dramatically with each remarriage, and a surprising number of people are actually remarrying their own spouses, you could cut the effective divorce rate down to 10% or lower, with this one neat trick.