We used to know what infidelity was: sex with someone other than your mate.
But the 21st century seems to have blurred those clear-cut lines. Is having lunch every day with an opposite-sex work friend a breach of marital trust? What about a flirtation online? If there's no sex, is it really cheating?
Such questions arise as societal and psychological pressures challenge deep-rooted ideas about the nature of infidelity. "We are as a society finally coming to grips with what it means to be faithful," says Douglas Snyder, a psychologist at Texas A&M University-College Station. "It doesn't just mean to have sex with someone else."
