The theory that adultery is "natural" for men, fulfilling their Darwinian need to spread their seed, has been around a long time.
But the connection women look for when having affairs may have evolutionary roots as well.
Using another partner to transition out of a bad marriage is one of the common reasons women have affairs.
"They are on a sinking ship and use it as a life raft because they don't want to just jump into the cold water," Reilly says.
"She might even have an extra child to create more genetic variety in her lineage; if some children die, others will live on." That theory is controversial and can’t be proven or disproven eons later.Women, she says, tend to have an emotional connection with their lover and are more likely to have an affair because of loneliness."Women tend to be more unhappy with the relationship they are in," Fisher says, "while men can be a lot happier in their primary relationship and also cheat."I was very lonely; I could never understand the concept of being lonely in a marriage until it happened." Diane began to flirt with other men to get attention, but she never considered having an affair.After a business trip with a friend turned romantic, she began a long-term affair, a path she admits she was likely on anyway as her marriage dissolved.