I would like to know how you define monogamy...if your definition is similar to what Chicup says below (long term pair bonding with polygamy and extra pair sex) then, ok...I agree. BUT if your definition of monogamy implies sexual exclusivity with only one partner for the rest of the individual participants' lives, then I'd have to disagree because that doesn't (and hasn't) work(ed).
Divorce rates are high, infidelity rates are high...and Sex at Dawn attempts to answer the question: in a society where monogamy is touted as the end all solution, why do we have such dysfunction? If we are a "monogamous" species (which, by the way, would be unique among the great apes and almost all primates), why is there constant variation throughout recorded history? Seriously, in a population of 300M (the U.S.), if only 1% were swingers, that would make 3 million people swingers...a population the size of Los Angeles...that is A LOT of evidence AGAINST our being and preferring monogamy (I know it's not a statistical significance, but 3 million is still a huge number)...and swinging is only ONE configuration of non-monogamy that exists.
The book attempts to show (by using scientific methodologies and meta-analyses) the external factors and artificial economic benefits for forcing a 'monogamistic' paradigm, but it argues against the fact that monogamy (as sexual exclusivity) is a preferred or successful configuration for human relationships as a whole...
See, the consequence of limiting your worldview to only your opinion, void of external influences, is that your worldview will be severely biased and shortsighted...kind of how the irreligious view the religious.
If objective and empirical evidence shows something contrary to what you think is truth, just ignoring it doesn't make you right and the evidence wrong...you can't bury your head in the sand and expect the contrary reality to disappear.
External 'influences' should be considered, critically analyzed and assessed for validity. Then, upon general consensus, the community (social, scientific, whatever) should agree with the evidence pointing to a truth (I say "should" because many times political partisanship screws with this). You can't ignore "external influences" and expect to have a grasp on reality...sorry.
I agree, even take for instance the Coolidge Effect...very compelling data that shouldn't be ignored. It's frustrating to see data like this passed over in the scientific and social science communities especially when applying it to human relationships. I believe that if more clinicians heeded this data, we'd see more success in resolving conflicts between partners of a primary relationship.