People are hardwired to move on after breakups and fall in love again, a review paper suggests.

Brian Boutwell, associate professor of criminology and criminal justice and associate professor of epidemiology at Saint Louis University, worked with his colleagues in analyzing the process of falling out of love and moving on to a new relationship. The team also identified the different evolutionary reasons why people break up.

His analysis showed that men are naturally inclined to leave the relationship after finding out that his partner had sex with another man. Men's brains are also hardwired not to raise children that don't belong to them.

Women, on the other hand, don't need sex to be the reason to break up with their partners because even emotional cheating is good enough to push them out. This is because women are evolutionarily hardwired to protect their resources for their children and physical protection.

"Men are particularly sensitive to sexual infidelity between their partner and someone else," Boutwell said in a press release. "That's not to say women don't get jealous, they certainly do, but it's especially acute for men regarding sexual infidelity."

But not all genders are the same. Some are willing to tolerate cheating. There are also some that need longer time to move on after a breakup due to environmental and genetic reasons.

"Our review of the literature suggests we have a mechanism in our brains designed by natural selection to pull us through a very tumultuous time in our lives," Boutwell added. "It suggests people will recover; the pain will go away with time. There will be a light at the end of the tunnel."

Boutwell described the falling in love and moving on process as a "mate ejection." He believes that more research is needed to better understand the problems that affect relationships and thus prevent breakups.

"If we better understand mate ejection, it may offer direct and actionable insight into ways in which couples can save a relationship that might otherwise come to stultifying and abrupt halt," he said.

The paper was published in the Review of General Psychology.