Monogamy...Possible or Antiquated?

So, this past Saturday, James mentioned to me that a couple we knew were in an open relationship. This was upsetting to James, since he saw them as an ideal, that a gay couple could be monogamous for the long term. I put forth my own opinion, pretty much stating that people, especially men, are not designed for monogamy and I think there is a shift in people's beliefs about relationships, sex and such. Essentially, I stated that we as a people were evolving. But, are we really? Does everyone share my thoughts on this?

More and more it seems I'm encountering more open relationships among couples. Why is this? Have people come up to the conclusion that sexual interest can fade over time? Are they comfortable with this fact and also comfortable with their respective partners being with someone else?

I've been hearing about open relationships more and more, today being briefly mentioned on "The Michael Baisden Show". How does one broach this topic with their respective other? Is the conclusion reached together? Is there any quiet resentment from the other? Do they consult each other on the other person that they want to bring into it? It's all very interesting and confusing to me.

My thoughts on it are if you're happy and secure, then by all means go for it. But, if you're relationship is on its last legs and you think this will fix it, then I think your middle name is naive. I'd like to think if this happened to me, I'd be open minded about it as I am now. But who's to say what emotional state I'll be in if this ever happened to me. At any rate, if it makes you and the other person happy and this feels like the healthiest way to keep your relationship going, by all means, do so :)