I had an idea myself for it, the idea that you have to renew your marriage after a set period or it just expires. For example, someone might have liked a person 2 years ago, but they've gotten fat and demanding, so they don't renew the marriage.

Marriage must provide at least twenty years of stability, because the primary societal purpose of marriage is to create a stable foundation on which to raise a child. Suggesting that we should normalise no-fault divorces after 1/10th of that time is insanity.