In the social era, it's never been easier to cheat, or more difficult to keep infidelity a secret.
Hookup apps and dating websites also present challenges to modern couples.
Websites like Ashley Madison are thriving. People are living a whole other world online because they can't be honest with their partner.
— Omolade (@mollysoulchild) June 4, 2015
— cliffoconda (@5secsofandom) March 10, 2015
In a recent Ted Talks, psychotherapist Esther Perel points out the difficulty with measuring infidelity rates.
"The definition of infidelity keeps expanding: sexting, watching porn, staying secretly active on dating websites," said Perel. "So, because there is no universally agreed-on definition of what even constitutes infidelity, estimates vary widely."
In fact, studies show anywhere from 30 to 60 percent of married couples in the U.S. will cheat, according to research from Buss and Shackelford.
Carolyn Bushong is a marriage counselor and life coach. She says behavior that begins through innocent texting and Facebooking can quickly spiral out of control.
"They start going back and forth, and enjoying it more and more, and then they start looking forward to it," said Bushong. "Then they start checking texts every 10 minutes, and it becomes an obsession just like any other addiction."
Couples often seek intimacy outside of their primary relationship because of dwindling passion, and a grass-is-greener mentality.
"At the beginning of a relationship, that passion is overwhelmingly wonderful. I think people do think 'oh, I could have that again,' and you can--but if you go down that road with someone else--what happens is you end up with them in a relationship again with all the responsibilities, and all the situations that take the passion away," said Bushong.
There is hope after infidelity.
Only 15 percent of couples divorce because of cheating spouses, and site unreasonable behavior as the primary cause.
Staying together in the wake of dishonesty takes a lot conversations, and even more hard work.
"That way, we can go back to the issues about no sex, or no passion, or feeling bored or ignored," said Bushong. "Sometimes, we can fix them."