In 2004, researchers looked at Swedish marriage data from the ‘80s and ‘90s. And they found some interesting relationships between a wife’s income and the likelihood of divorce:
Divorce Risk for Couples as a Function of Wife’s Share of Income
Source: Max Planck Institute
In general, divorce risks increased as wives contributed a higher share to total income. We see this most clearly with the lowest, 2nd, and 3rd income quartiles-- the likelihood of divorce is lowest when wives contribute little or nothing income-wise. On the other hand, the likelihood of divorce is at its highest for all income levels when women are the main breadwinners. When a couple is rich, but the wife is really rich, they are most likely to break up by far.
Researchers Guiping Li and Andres Vikat bring up a possible explanation for this trend. While there’s a considerable financial risk for a stay-at-home wife to get a divorce, “a wife who enjoys higher earnings than her husband has a lower economic threshold to leave an unhappy marriage.”
Money buys you options, including the option to get divorced.