"The female myth is that all men screw around," says Atlanta psychiatrist III, M.D., author of Private Lies. In recent years, an increasing number of women have used that as a convenient rationale for having affairs of their own. "To some women, at least, men's alleged unfaithfulness makes their own screwing around only fair- it's not so much a flaw of character as a blow for liberation," says Dr. clinical professor of psychiatry at Emory University School of Medicine in Atlanta.

At the same time, he says, men seem to be having fewer affairs. The cultural ideals of masculinity have begun to shift, so the debonair affair is no longer socially acceptable behavior, no longer an admired male sport. As a society, we treat th'e infidelities of a Gary Hart far more harshly than we did those of JFK.

Still, despite the fact that affairs are surprisingly common, they should not be taken lightly. Marital infidelity is "the primary disrupter of families, the most dreaded and devastating experience in a marriage," notes Dr. "It is the most universally accepted justification for divorce. It is even a legally accepted justification for murder in some states and many societies."