The Trump conversation was brought up to illustrate the point that if the topic of sex loses it's stigma then not everyone is going to talk about it the way we would.
While I've made the effort to not follow in my dad's footsteps with my kids, I haven't really with other guys. I don't know how you and I should talk about it. (Cara is very private and actually admonished me not to post anything too personal here.) I think I probably could have saved myself a lot of trial and error over the years had I taken the time to compare experiences with other guys.
How should our wives? Again, comparing experiences could save a lot of trial and error. Of course I'd be embarrassed by them commiserating over my and your mistakes in bed, but I'd get over it.
As to wider circles I guess it would depend on whether it was pertinent. I had a coworker who loved recounting tales of his sex life which never really bothered me, although he had a much larger sample set. He never pushed me too hard to share either, so the conversation was fairly one sided and focused more on the art of seduction than particulars of the act. It also never happened when there were any female coworkers around.
Polyamory is, I think, not more widely consider for the non-religious reason of jealousy. This is probably rooted somewhat in the idea that one's mate is one's property, but not sure that even getting beyond that culturally would end the potential for jealousy. I've read that compersion is a healthier response and people have been able to get beyond jealousy in a variety of other situations. If the non-aggression principle implies that people cannot be property in the sense that one cannot own the body or labor of another, then non-monogamous relationships cannot be immoral. The question becomes murkier, I think, when deception is involved, but I haven't seen a good argument that the non-aggression principle implies lying is immoral and if there is no property involved (because people can't own eachother) then I don't think it's fraud either. But lines of thought such as this are the reason libertarians are often accused of being libertines!
Very true.
I recently read the book Sex and Dawn which you might appreciate. As for posting or talking about this stuff, I'd definitely get the permission of my spouse first because that is a very intimate, private act. Unless they are comfortable talking about it, I won't be comfortable talking about it.
I think fraud and trust go beyond property rights into tribal norms, game theory, and such. You can read more of my thoughts about that here, if interested.