Pretty much as I would expect......you're consistent to say the least. You're right; it was not an official statement from Psychology Today, rather from someone writing for them. The book that mentioned that the majority of cultures were polygamous is called Motivation I think. It was a Psychology text from when I was in school. I still have it, so I will double check on its title. The figure, if my memory serves me correct, was that approximately 2/3's of cultures practice polygamy.
To address some of your comments about women being gold diggers and people evolving, I would say that your optimism for the current human condition is really cute. I remember Bil Maher saying, "You can't reform biology!" Well said Bill. He, of course is not entirely correct, as you could, with enough effort, reform many of our worst behaviours; or best for that matter. So, the question becomes, what are our natural predispositions?
Your position, as I have interpreted it, is that because the past is behind us we should think and act differently from how nature shaped us. This is missing a big part of what the biological evidence tells us. Take for example the notion that women are all gold diggers. It was never mentioned that they are all gold diggers and the quote from Psychology Today was only a generalization. So, is it true that women, in general, are gold diggers? I would posit yes. Gold diggers seems a little harsh though, and it is not really fair to use that language when referring to a naturally evolved and very useful, though at times, rather antiquated set of behaviours that sometimes manifest themselves in the form of what we today call "Gold digging". Also, your notion that people evolve is improperly used I think. I think you mean that cultures evolve? Though it is true that we have evolved from other species, we essentially have the same brains that we had 100,000 years ago, though there are some minor differences, perhaps mainly a slight thickening of the neo-cortex. Where the problems lie is in the disparity between our rapidly evolving cultures and technologies and our somewhat stagnant brains and accompanying behaviours. This is where your arguments lose steam. We are not as plastic as I think you believe. Sure, cultural expectations have evolved, but a lot of our behaviour is the same. This either forces our culture and society to accept the behaviour, thus helping to drive the cultural evolution, or to force the behaviour underground. Two sexual behaviours come to mind. Homosexuality and pedophilia. One accepted, thus forcing a cultural shift, the other not, thus forced underground. The biological wiring that makes for such predilections has long existed, and the culture must evolve in ways to deal with it. As for polygamous type behaviours, I would put forward that it is wired within us and that it is not human evolution that explains a shift in this particular mating behaviour, rather a cultural and societal shift.
As for exciting the Feminists, it’s easy. All you have to do is make some argument that suggests nature superseding nurture and that the current state of affairs is the natural state. That’s not to say though that it’s the desirable state.
The only glitch in our system is that my gf's bf does not know that her and I and sometimes my hubby get together for a romp sometimes. He thinks she's straight. 