"I don't know what tell you IJ---I think its a reach that you equally love multiple people---the idea that you can love multiple kids is predicated on being around them from childhood. My feelings for the friends I have had since I was a kid are stonger than the feelings I have for friends I have made recently.......its just how people work."
That's your experience; mine differs. Perhaps that's why you think this wouldn't work and others do. Another reason is that you are content to dismiss data without even knowing what it is. As you point out, I haven't seen all the data possibly available, but I've seen more, and I'm not dismissing findings I'm not familiar with. It doesn't make much sense to indict me for having opinions based on having read a whole book about it.
"The oldest codified laws from as far back as we can check had rules/laws pertaining to adultry and even "primitive" hunter gatherers in the recent past had pretty serious penelties for women sleeping around."
I'd be interested in your references.
"So I'd guess that whatever examples the author can produce there are more counter examples."
This isn't an issue where they negate each other; if two authorities produce examples that differ, that merely illustrate that it works for some societies and not others, which I'm perfectly happy to accept right now. My point is only that our nature permits it and when culture doesn't, divorce, adultery and dissatisfaction are common. (Same applies to your observation that nonadulterers may be as common as adulterers. Ok, they're both common, agreed).
"Even out closest animal relatives (bobono's aside) become hyper violent when somebody else tries t co-op "their" mate. Males and females both.........and sure both sets sometimes fool around.....but the anger over it seems hardwired into them.......so I doubt its wholly cultural."
Actually.... the authors beg to differ, and they present a detailed analysis of our social, genetic, and anatomic relationships to the other great apes and our closest relatives are basically promiscuous and peaceful with minimal sex dimorphism and relatively oversized "junk." I would need to see some real specifics or references to refute the lengthy account I just read.
As for what constitutes "little" sexual excitement, the term is deliberately vague, but every account I've ever read documents a decline in frequency and satisfaction over time. Not overall necessarily, but the passion phase definitely declines. I can research a detailed response once you invest similarly in less commonly accepted theories / theories that differ from the research you haven't read of your own.
"Maybe if they spent as much time working on their current relationship instead of the time and energy in getting and maintaining a new relationship, they would not be having problems."
Are we talking about.... average married people in the USA? I don't think constantly searching for new mates is really standard practice in this culture and yet frequency and interest commonly decline.
"In terms "lots of people" (your term) that live that way now........I'd again check the actual numbrs of people that currently live in places that allow multiple wives ......and the number of people that actually do it."
You mistake my meaning. I didn't say, "multiple wives." I'm talking about people who don't settle down with one partner for life the way culture says we should, the way it's supposedly natural for us.
"Besides, why bother to go thu all the stuggle to be able to "marry" at all if your just going to skip all that "fidelity" stuff and move right to an "open" arrangement?
Multiple relationships would seem to create more confusion about whom had "rights" to what than the present situation."
I assume you're talking about same sexers here? I don't speak for all gay people! We're not "homogenous!" I support people's right to marry because.... I support equal rights, that's pretty basic. Lots of those gays will want monogamous relationships or won't marry, while dating other people; some will have lesbian bed death and hardly mate at all

I mean, really--do you not think that most straight guys would find it awesome if their wives said they could have Ashley Greene or other partners on the side?? They'd love it! So does it surprise you that some gay guys in stable relationships think it would be cool to have a little Jake Gyllenhaal or whomever now and then? Please tell me you're not actually shocked.