Poly life-style is certainly not for everyone and you’ve made a lot of good points here, but it really can work and work wonderfully, at that. I too used to be a skeptic and the road to where we are now was not without significant growing pains, but grow we did and we are now happier than ever. And yes, it’s true that many people don’t bother to do the hard work necessary to go about this ethically and honestly, but having done so benefited our relationship with each other, in part because it forced us to have conversations that most couples never have to have. We know ourselves a lot better now, as well as our relationship with each other better too.
I have a secondary partner and my husband and I see other people as play partners from time to time. We see them together as a couple, so that cuts down on some of the time management issues. I’m entirely a pragmatist, so I give little thought to whether it’s theoretically anything or the other; only whether it makes both of us happy and fulfilled, which it very much does. A part of that is about sexual satisfaction, but since sex is on the lowest level of Maslow’s hierarchy of needs, along with food, water, air, sleep and the like, I’m going to have to say that having multiple connections with multiple people, some of whom we love, meets a variety of other needs also.