CHICAGO (CBS) – Infidelity is pretty common. One study found up to 60 percent of married men cheat. The question is: which men cheat? What do these cheaters have in common? CBS 2’s Susan Carlson found some answers.

RELATED STORY: Why Women Cheat On Their Husbands

A woman we’ll call “Kathy” didn’t want us to reveal her identity because of something that happened seven years ago. Right before their third anniversary, her husband dropped a bombshell.

Kathy says he told her, “I’m in love with somebody else and I’ve been in love with her since before we got married.”

So what drives a man to cheat?

People we stopped on the street had various opinions.

One woman thought that it was because men were “just being unhappy and wanting something more.”

A man said, “If she’s not being around him and spending time with him, man, he’s gonna look somewhere else.”

That’s what you might think, but not always.

When Kathy was asked what was different about her and the woman her husband left her for, she answered: “In terms of our status, I am far more educated, and I was in a very senior position at a big company, and she took a job as his paralegal.”

Kathy supported her husband and he left her for a woman who made much less money. She’s not alone.

A Cornell University study found men who depend on their wives or girlfriends for financial stability are five times more likely to cheat than men who are not dependent.

Therapist Dr. Alexandra Solomon from The Family Institute at Northwestern University said, “He may turn away from the marriage because he feels like he’s failing in that provider role, and he may seek that ego boost elsewhere.”

And in these tough financial times, Attorney Corri Fetman believes: “They may be cheating more, but they’re staying together and living in the same household. That’s what I have found.”

Fetman says divorces are down, but couples’ therapists at The Family Institute at Northwestern University saw a record number of patients last year.

When it comes to cheating, Dr. Solomon says there’s another key difference with men: their brains are wired to compartmentalize their relationships.

“Men can report normal or good levels of marital satisfaction and be engaged in an affair,” she said.

And for whatever reason, women tend to be more tolerant of a man’s indiscretions.

But staying together wasn’t an option for Kathy.

“I think I’m probably a stronger woman after all of this, but it was a high price,” she said.

When it comes to a woman’s motivation for cheating, it usually has to do with something else all together.

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