Anyone who’s been cheated on in a relationship knows the question that hits the hardest is Why? As quick as we are to condemn infidelity, the reasons why people cheat often aren’t black-and-white—and ...

I got an email the other day from a journalist who was writing an article about why men cheat. "I'll probably be paying the most attention to Cheryl Cole and her recent marital problems," she wrote.

Mr. Gideon, a young banker, is married to a very beautiful lady, Martha, who dotes on her husband. Martha does everything to please him and is even ready to give her life for him. But like most men, ...