Perplexed as to how Jesse James could have had the audacity to cheat on his superstar wife, Sandra Bullock? Or why Eric Benet walked out on Halle Berry (I mean who says no to Halle Berry!)?

A new research may help unclog this stupefying mystery. Men who make considerably less than their female partners, or who take home nothing, are probably more likely to cheat than those in relationships where incomes are relatively identical, the study found.

In fact, men who were completely dependent on their partner's income were five times more likely to cheat than men who contributed an equal amount of money to the relationship, according to research presented at the annual meeting of the American Sociological Association.

A man who makes significantly more money than his girlfriend or wife is also more likely to cheat because the job or position he works may require long work hours and travel. Those factors could create an easier environment for cheating, the study suggests.

However, dependence on men does apparently make women more likely to be faithful.

Cornell University sociology graduate student Christin Munsch says that, "Having multiple sexual partners may be an attempt to restore gender identity in response to these threats," she goes on and writes. "In other words, for men, sex [outside their relationship] may be an attempt to compensate for feelings of inadequacy with respect to gender identity."

The study claims, "The Effect of Relative Income Disparity on Infidelity for Men and Women," examined married and cohabitating people between the ages of 18 and 28, who were in the relationship for more than a year. The study uses data from the 2002 through 2007 waves of the National Longitudinal Survey of Youth.

Munsch points out that in the overall study, very few couples surveyed had experienced cheating during the six-year period studied. Only an average of 3.8 percent of male partners and 1.4 percent of female partners cheated during that period.