According to new research, the saying "once a cheater, always a cheater" holds true.

University of Denver psychology graduate student Kayla Knopp studied 484 unmarried adults aged 18 to 35 to find out if people who stray in one relationship are more likely to do so in the next. Her findings were presented at the annual American Psychological Association convention in Washington D.C..

Knopp and her fellow researchers asked participants questions such as, "Have you had sexual relations with someone other than your partner since you began seriously dating?" and "Has your partner had sexual relations with someone other than you since you seriously began dating?"

Those who admitted to having sexual relations outside their relationship were three and a half times more likely to do so in their next relationship as well, Knopp explained to The Huffington Post in an email.

"This means that of those people who said they had sex with someone else in their first relationship, about 45 percent said they also had outside sexual contact with someone in their next relationship," Knopp said.

The cheating pattern carries over into the lives of non-cheaters as well; participants who had unfaithful partners in their last relationship were three times more likely to be cheated on again. And people who suspected their partners of cheating were 10 times as likely to be suspicious in their next relationships.

"We can't say for sure what this means," Knopp tells The Huffington Post, "But I think it indicates that how people are feeling about trust, fidelity, and commitment in their relationships is even more salient than what their partners are actually doing."

The study does have its limitations, however. As Knopp explained to The Huffington Post, she and her team specifically asked participants about "sexual contact" with someone other than their partner, which doesn't include non-sexual infidelity such as emotional affairs, online relationships, sexting, or even behaviors like kissing. The sample also didn't include people in same-sex relationships.

Still, there's a lot to be learned; while the study doesn't reveal why people cheat, it can help those who have been through it plan for the future.

"Our advice would be to talk with your partner about your relationship histories. If one or both of you has had trouble staying faithful in the past, what happened then? Might it happen again? How can you and your partner anticipate those difficulties together, and tackle them as a team?" Knopp advised. "Many people expect monogamy and fidelity to just happen easily, but we know that isn't true. Commitment takes effort and communication, and being able to confront the possibility that you or your partner might struggle to maintain fidelity can make you better able to handle those challenges in the future."