The divorce rate could be 99% without GP's situation ever happening. This stat says nothing by itself.

Even if the situation really did happen multiple times, it's entirely possible that something else caused the divorces, e.g. people who came to money like this could turn out to be bad parents/partners on average. I mean, seems like there's plenty of examples of riches frying people's brains right now...

You say “mostly initiated by the woman” like it proves something about women maliciously ending marriages to make off with their husbands’ earnings. Have you met men? Many are eminently divorcible. A lot of people have bad relationships that should’ve never started, and it’s not surprising that it falls to the woman to eventually call it quits.