I suspect that there are deeper compatibility issues at play and major events like infidelity or job loss just act as catalysts for divorce.
Humans are complicated. They have a lot of different needs that all have complex relationships with one another. Everyone experiences theses needs to varying degrees. If the needs that aren't adequately satisfied aren't outweighed by those that are, then it's reasonable for a person to start looking elsewhere to satisfy those needs.
If my wife became a huge economic burden and wasn't contributing anything else to the relationship, then after a year or two I'd definitely be thinking I could do better.
You could begin to support such an explanation by pointing out that less women work and so less women are able to lose jobs and so less men divorce them because of it. But that only explains half of the divorce inequalities described by GP. Do men really cheat significantly less than women?
So we arrive at a point where either it's more socially acceptable for women to divorce men because of job loss than the reverse (GP correct), or it's more socially acceptable for women to cheat than men (GP incorrect).
Conversely, either it's more socially acceptable for men to divorce women for cheating than the reverse (GP correct), or it's more socially acceptable for women to be unemployed than men (GP incorrect).
Interesting!
Of course, this is all based on anecdote. Also maybe I oopsed and strawmanned inadvertently.