I think this works in this way:
1. Divorce first started to become socially acceptable in the 50s, 60s, and 70s. At the time, many marriages that were undertaken early or under outside influence. These unhappy couples began to take advantage of their newfound ability to separate with no social stigma. Divorce rates skyrocketed.
2. Once this wave evened out, it became much more accepted that individuals should only marry those of their choosing. With that, people wait longer to commit and take the commitment more seriously. Which leads to lower rates of divorce.
Marriage has transitioned from an externally imposed institution, to a choice that people make. This leads to more consideration when committing and lower rates of divorce.
Hopefully, it also leads to a stronger society.
^Day 15/90 149 words