Tonight I went to the theatre and saw live opera. The production was littered left and right with themes that could be interpreted through an evolutionary lens. I came in late to the production and left early, so I am bound to have missed a few things.
In a nutshell, two women have fiancés who go off to war. The ladies are dreadfully distraught with the abandonment. A guy makes a bet that he can get these ladies to have affairs while their men are away. Although he is confident the ladies will prove to be unfaithful because that's what he knows women do, he nevertheless enlists the help of their maidservant who will get paid if she helps set the ladies up with two men he has chosen - rich, handsome, healthy foreigners.
From an EP perspective, why would these ladies be unfaithful? They might be tempted to cheat for a variety of reasons.
In this context, hooking up with a new guy can be an insurance policy against the death of the fiancée. Let's assume these women were already "knocked up" by their fiancés. If the father died in the war, who would provide for the offspring? Back up man. Why would he provide? Providing for the child shows he is a good father. He might be able to translate that into having his own offspring with her.
Or, he could do what some primate males do when a child is born who "is not of his blood" - kill it. Infanticide is one male reproductive strategy. By killing her child and otherwise acting domineering, he might intimidate her into staying with him and having his children. Primate females have evolved strategies for dealing with infanticidal males, but none of these do much good if the woman is dependent on that man.
Even if she didn't get knocked up, or wasn't already preggers, she could benefit in other tangible ways from having a short-term affair.
But what if these women don't need a provider? Let's say these ladies are from wealthy families or are otherwise able to provide for themselves and potential dependents.
They might be tempted to cheat if these suitors are handsome and physically fit. They might have "good genes" that could be passed on to her offspring - genes that would make her children more desirable as mates themselves. Poor women would be tempted by this too. But in this scenario, the rich women could have a fun little affair and ditch the guys when the fiancés come back from the war without worrying about the loss of a provider.
They might even become pregnant with a more handsome man's baby. And if they can convince the fiancée the baby is his, well bingo for the woman - she will have successfully cuckolded the fiancé and settled down with a war hero. She risks an awful lot if she is caught in the ruse though. War hero may desert her and the baby. No big deal - if the woman is financially independent, she doesn't need him to stick around and support her and her dependent. Good riddance.
He may try to kill her for cheating. Nothing less would be expected of a man who just returned from participating in state-sponsored murder. Even men who aren't fresh off the front lines can be violent and physically aggressive when consumed by sexual jealousy. If she is a wealthy heiress, she probably has "back up" in case he turns homicidal.
As you can see, poorer women risk more by being unfaithful. They also potentially benefit more. Wealthy women have less to gain and less to lose by being unfaithful.
There is much more to the opera storyline than a simple tale about infidelity during war. There is also much more that can be said about reasons for female infidelity. As I walked away from the production after the first act closed, I lamented not being able to discuss the themes from an EP perspective with my students. That would have been fun. They would eat that stuff up. I miss my Thursday night "mating seminars." They were the liveliest discussions ever.