In his research, Gary uncovered the number one complaint cheating husbands have about their home sex lives. "Believe it or not, the majority say it's frequency of sex," he says.

He says he finds this surprising because so much media targeted to women try to stoke other worries. "Women's magazines make women believe that they have to have a PhD in prostitution education or else the husband's going to cheat," he says. "It's just a matter of frequency."

Gary says sex for men is an emotional act, and a woman initiating sex is "like getting flowers and him washing the dishes for us."

"It's saying that I adore you, I care about you, I want to do something nice for you. It's a way that they connect," Gary says. "He wants to do it with you because he wants to feel love. He wants to have that loving connection—the touch, the feel, the sensuality, the passion that comes through a sexual connection."

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