Jude Law cheated on Sienna Miller, Peter Cook did it to Christie Brinkley, Kate Hudson reportedly did it to Chris Robinson and rumors have been flying recently about whether New York Yankees star Alex Rodriguez is doing it to his wife, Cynthia.

But infidelity isn’t just confined to rich and famous, and experts say it has a lot to do with ... temperature. Flings, they say, are a summer thing.

“Warmer weather has a huge impact on our hormones,” says Patrick Wanis, a relationship expert for Playboy Radio and Cosmopolitan magazine. “Summer is the most sensual and erotic time of the year. We show more skin, we’re emotionally more open and there are many more social and vacation opportunities to be led astray.”

Click here for FOXNews.com's Wedding Season package

Men are particularly vulnerable to temptation, according to the Journal of Couple & Relationship Therapy. The journal, which presents clinical, theoretical and research articles on relationship treatment issues, says between 50 and 60 percent of married men engage in extramarital affairs.

So add hormones to a heat wave, and you have all the more reason to keep a close eye on your guy.

“By nature, men are stimulated visually,” Wanis said. “So of course, when summer rolls around, more flesh is being flashed. Men also tend to have a lower value system than women and are better at separating sex and emotion.”

But women's values apparently aren't much better — the ladies don't lag far behind on the infidelity meter. According to the Journal, 45 to 55 percent of wives have a wandering eye.

So what makes summer the season for cheating?

“Many wives/husbands use summer as an excuse to go on separate vacations like fishing trips, camping or a girly get-together at the beach,” warned Ruth Houston, author of “Is He Cheating On You?” and founder of infidelityadvice.com. “There’s also the summer bogus business conference and many more chances to stay out late.”

And if one chooses to "moonlight" with a little on-the-side romance, what kind of person does he or she generally look for?

Houston says men are looking for fun, so they pick younger, less-serious women. But women cheat with older, attractive and wealthier men who can spoil and seduce them.

Even the strongest romantic relationships can fall prey to affairs. Houston says some cheaters feel that their marriage is so stable and stainless, their spouses will never suspect they're having a fling. They also feel a little rendezvous won't have any impact on their relationship.

On the other hand, Wanis argues that all infidelity takes place as a result of something lacking in the love department.

“For someone to stray, something has to be missing in the relationship to start with,” Wanis said. “This could be an emotional problem or a physical problem, such as an unfulfilling sex life.”

Many cheaters make the mistake of assuming that a summer affair is strictly about sex and will be over when the leaves turn brown, Houston said. But if the two-timing goes on for too long, a hard-to-break interpersonal connection may be formed.

“The number of my consultations with infidelity victims sharply increases at the end of summer,” she said. “This is because a lot of relationships are beyond repair as the cheater has had time to connect emotionally with their seasonal lover.”

Gary Edwards, a 47-year-old British businessman, confessed that five years ago, his summer fling flung from sexual to spiritual.

“My fiancée at the time was either refusing to deal with it or had no idea because she never even questioned me,” he said.

“She was in London while I was doing a contract job in Paris. I thought my French fling would finale when I moved back in September, but by then it was past the point of physical and I wanted only to be with her. I broke it off with my fiancée but never honestly said why.”

Houston’s research shows that two out of three extramarital affairs go undetected. So what signs should a suspecting spouse look for?

Both Wanis and Houston advise keeping watch of subtle signals, such as changes in personality, altered eating behavior as well as texting, talking and typing at odd hours — not to mention obvious cues like taking an overnight bag to a golf game.

Most importantly, they say, if you suspect something, follow your instinct.

“Always go with your gut and intuition,” said Wanis. “You know deep down when something isn’t right, but many of us tend to go into denial.”

Houston adds that suspicious partners should not approach their loved ones without solid proof.

“If you’re wrong, this could do more damage than even infidelity would have. But if you have the evidence, you both need to sit down and discuss the situation," she said.

Betrayed partners also differ in how much they want to know about the affair. Some people want all the details, while others want just the bare minimum, Houston says.

And should you decide to forgive a cheater, make sure he or she knows you won't soon forget.

“Cheaters will become repeaters if they don’t suffer serious negative consequences, like losing their family or reputation,” said Houston. “Part of the thrill is getting away with it, so be savvy to the signs. One will never learn unless they lose something special.”