Monogamy as Evolutionary or Social Function?

http://dsc.discovery.com/videos/science-of-sex-appeal-is-monogamy-the-answer.html
http://dsc.discovery.com/videos/science-of-sex-appeal-is-monogamy-the-answer.html

These videos described the reasons for monogamy in humans. In recent decades, I think people's view of monogamy has changed greatly. Maybe this is due to an increasing feeling that life-long monogramy isn't necessary or practical. With half of all marriages ending in divorce and women's changing roles in society, it isn't really surprising that monogamy isn't seen as a necessity to building a prosperous family. Today, women can engage in one night stands as easily as men and with less worry about consequences than ever before. They also aren't dependent on men as providers anymore. So is monogamy still a good option?

These videos showed that although women throughout evolution wouldn't have benefitted from straying from her partner, women seem to have a tendency to desire different traits at different times of the month. They still desire good fathering traits in their long term partners; however, they may stray if their partner doesn't have the good genes needed to be passed on to offspring. These "good genes" can be recognized by attractiveness and may tempt women into cheating, especially when their liklihood of getting pregnant is high.
Both men and women were found to have chemicals in their brains that support monogamy. These were vasopressin in males and oxytocin in women.

So could monogamy be nothing more than the balance of hormones? I think that even though monogamy today might not be as necessary as it was before, it is still necessary for future generations. Two parent households seem like they would be ideal in raising children. This way the children have both a male and female perspective guiding them and they often grow up with more stability.
Studies like Buss's Strategies of Human Mating show that men think short-term dating is more important than women. I understand that this could be because it is the easiest way to ensure they mate. However, I think that from an evolutionary standpoint, the offspring of a male who wasn't present for their upbringing would have less of a chance of surviving. This is possible for several reasons such as a lack of protection and no one to provide for the family. There would also be a chance that the child would have no male to teach it hunting or other important skills. Then in this way wouldn't the offspring of an absent male be less adaptive and less likely to mate? All-in-all I think that although monogamy isn't essential today, it is still important in raising successfull offspring in most cases. And although short-term mating may be the easiest way for males to reproduce, it might not have given their genes the best chance of being carried on through future generations.