I'm not sure how "scientific" the article is, and I'm not sure the written material supports the title of the article completely. We should remember, that Mankind has evolved in a special way; and our culture, as well as our biology have combined to assure the survival of the species. For instance, human adlolescence lasts, depending on the culture, perhaps 15 or 16 years? A long time; and we are dependent on our family for survival. For most of our evolution, Mankind was a tribal animal; surviving in small groups, dependent mostly on our fathers, mothers, grandmothers and grandfathers. It takes many years for the complex human brain to develop into a fully functioning adult, therefore the long dependence is necessary...it's not like a bird, that is on its own in six weeks, or a cow that can fend for itself in less than a year.
Sex and monogamy, I believe was designed to keep the mother and father (who were in a tribal situation were also very interdependant) pair bonded for as long as it takes to raise their children to maturity. Lifespan 100,000 years ago was probably in the range of 30 years; so it made sense. The tendency to stray I think is one aspect of our tremendous adaptability; a trait that has enabled the human race to survive all of the evolutionary pressures, including monumental climate changes. Bottom line; I think monogamy is the more "natural" state, as opposed to "unnatural".
While I'm thinking of it, there's an old book that I read many years ago, entitled "The Naked Ape", whose author excapes me right now. One of the themes of the book concerns sex and monogamy. Sex for the human is an order of magnitude above all other animals; it is designed for intense and prolonged pleasure as part of the pair bonding. He goes into a lot of description and comparison to other primates, but the arguments are pretty convincing.