Another Look at Ex Post Facto Civil Laws

A few years ago, I posted that we might need a Constitutional Amendment to ban ex post facto civil laws:

There were people who got married a few decades ago under the impression that marriage was until “death us do part” only to find their marriage vows had been changed into something temporary. The late Terri Schindler Schiavo said that she didn't want to be kept alive by extraordinary means followed by the Florida state legislature passing a law that changed the meaning of “extraordinary means.”

I just realized that the Constitutional clause banning Law impairing the Obligation of Contracts bans many ex post facto civil laws (at least on the state level).

What does this imply about no-fault divorce?