Evolutionarily, it only partly makes sense, because there are two male evolutionary strategies for passing on their genes. Either have sex with as many healthy (and wealthy) women as possible being always on the move or have sex with one healthy (and wealthy) woman and make sure that as many children as possible from this relationship grow up to have sex themselves.
Let’s say about 30,000 years ago a male gold digger chasing a healthy and wealthy woman he doesn’t like and with whom a relationship doesn’t work won’t offer good support for his offspring to grow up and have sex themselves. The bears and tigers will get them first. Or the group of hunters and gatherers cannot rely on a critical mass of reliable people finding food and shelter. Social relations matter very much. Greed can be a serious danger.
A good monogamous relationship is about good support for the offspring. The grandmother effect and menopause supports this model, because some point during evolution, it became advantageous for females to stop dividing their declining faculties between the care of extant offspring and the production of new ones. Since a female’s dependent offspring would die as soon as she did, he argued, older mothers should stop producing new babies and focus on the offspring they already had. In so doing, they would avoid the risk of dying during childbirth and thereby eliminate a potential threat to the continued survival of current offspring. In addition, postmenopausal women can contribute knowledge and skills to other group members to enhance group fitness.
http://en.wikipedia.org/wiki/Grandmother_hypothesis