First off, I have to admit that my scientific knowledge is a bit sketchy on this one. Nevertheless – my impression is that there is a (scientific ?) consensus out there saying the following:
The nature of men is that of the restless promiscuous hunter. Evolution has provided pressure towards maximizing the spread of male genes through procreating with as many women as possible. This way the number of offspring one man can obtain is maximized. Apparently observations supporting this view are the vast amount of sperm cells produced in the male reproductive organs and the continuous (not cyclic) nature of this sperm-production. The logic is, I think, that the production of all these sperm cells would be futile if destined for only one woman with a cyclic reproduction cycle. So far so good.
Consequently, the masculine “nature” is continuously compromised in our modern monogamous lifestyle. Male infidelity is often excused using the arguments above. The same arguments also makes domestic life and caring for the family into a compromise with “natural” masculinity.
Still good ?
Even if making as many offspring as possible seems like a good strategy to pass on (male) genetic material, isn’t it possible that another strategy would work just as well.
You could argue that continuous sperm production is present to counter a single woman’s unpredictable cycle, – or compensate for miscarriages, – or compensate for children born by this woman dying young (not so rare in those older days). This make-one-woman-pregnant-many-times strategy could potentially lead to as many offspring, themselves reaching reproductive age, as the multiple partner strategy.
If you buy into that last argument, there is no reason why the selective pressure on men has been towards domestication and taking maximal care of his one-woman family. And, against inclination towards infidelity.
I’m so sorry for ruining our excuses here my fellow men, but the whole man-as-a-hunter-excuse has been bugging me for a long time. I find it hard to understand why such an idea has been elevated to universal truth. I believe a need for behavioral excuses has overridden scientific rigor on this one. Anyone who can convince me otherwise is more than welcome.