> a lot of men tie their identity to their employment so strongly

I wonder if the other side of the coin isn't that wives tend to respect their husbands less when these earn less than they do. It could be because it violates a social norm caused by society's gender role expectations.

Research found that even employed men who earn a bit less than their wives are affected by higher divorce rate.

So we can cast these men as insecure and emasculated, or it could be a mix of both men and women's reaction to the situation, along with many other variables that you've hinted at.