Do you know someone who has cheated? Chances are you do. Fully 52 percent of Americans say they know someone who has an unfaithful spouse, according to a nationwide USA Today/Gallup Poll of 1,025 adults.

When the same question was asked by the Harris Poll in 1964, only 24 percent said they knew someone who had a cheating spouse. So that number has more than doubled in a little more than four decades. What's remarkable about this isn't that people are cheating more frequently--they probably aren't--but that they're talking about it.

"My inclination is that there has not been a change in the actual behavior of people, but there has been a change in the inclination of people to discuss it," David Barash, an evolutionary psychologist at the University of Washington and co-author of "Myth of Monogamy: Fidelity and Infidelity in Animals and People," told USA Today reporter Sharon Jayson. He says we humans have an evolutionary tendency to have multiple partners, but that doesn't mean we have to cheat. "It's important to understand the inclination is there," he told USA Today. "Monogamy is difficult. It's not dead. Realize it is possible, but you have to work at it."

Fun findings from the USA Today/Gallup Poll:

• Which is worse for a husband to do: Have paid sex with a prostitute or a have a romantic liaison? Men said the affair was worse, but women said the prostitute was worse.

• If you found out your spouse was having an affair, would you leave your spouse and get a divorce, or not? Among all adults, married and unmarried, 62 percent said yes and 31 percent said no.

• Could you forgive an affair? Among married men and women, 37 percent said they would definitely or probably forgive a sexual affair, compared with just 30 percent of singles. That leaves a lot of folks who couldn't forgive such a transgression.

• When asked if they would stand next to a spouse at a news conference to address the issue of the spouse's infidelity, only 36 percent said they would do this.