Hum... I recently ran across an abstract of a study suggesting that relative incomes levels in marriage not only effect spouses' behavior in “obvious” ways (for example, as a spouse contributes a greater proportion of family income they have more say in how it is spent) but that behaviors often perceived as mostly unrelated to income differences are also subject to shifts with the relative earnings advantage, for example that which partner gives and receives the majority of oral sex may shift – and can shift back - with substantial changes in relative income.
That has to be the stupidest thing I've ever heard.