I'm gonna post more about this on my blog later, so as not to continue to threadjack. One thing, though --
"but the comment you made telling her to do that just made me wonder what the hell the benefit was in the first place if you have to make sure it isn't part of what's fucking things up. But I never said nor meant to imply that D/s was the cause of their problems, though couldn't it exacerbate them, just like poly can magnify problems in a relationship? (Though I do not like correlating the two. I see poly and any aspect of BDSM as vastly different choices from each other)"
I've gotta say, I think you're being inconsistent here. You ask what the benefit of D/s is if it could be part of the problem, and then you point out that poly, too, can exacerbate problems in a relationship. Why add poly to a perfectly good marriage if it could end up being a problem? Why add sex to a friendship if it could end up being a problem? Because usually it's not a problem, usually it's *awesome* (at least when you're experienced enough to know what you're doing).
I think the comparison to poly is apt because both are relationship choices that the world at large finds confusing at best and disturbing or immoral at worst. It's true they're very different in other ways, but so are carrots and jogging, and yet I can make the comparison carrots are to candy as jogging is to lying on the couch. Metaphors can compare unlike things and still be valid.
Also, if you've read other sources and still feel you don't understand... and would like to understand... do at least consider the xeromag.com link. Veaux writes in an extraordinarily clear, relateable way and assumes not just lack of knowledge but active resistance, at least initially, in his audience.
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.