If it was the men who were, on average, disproportionately divorcing their wives the framing could be reversed. As divorce has costs, the act of divorcing someone indicates that they are worse as a spouse than the alternative.

I had remembered reading that women tend to be less happy in marriages than men, but this appears to be wrong. Still:

> happiness increases when low-quality marriages dissolve—again, that’s true for both men and women.

https://greatergood.berkeley.edu/article/item/is_marriage_re...