Look...

Not that I am into gadgets, but even with my very cursory and rudimentary knowledge of gadgets I am aware that so far all the efforts that have been put into the design and creation of a universal gadget that is the best have failed.

When I can afford it, I will buy a navigator, because the driving navigation on the Android is not good enough. Nice try, but still it is better to have a cell phone and a navigator separately.

Likewise, to the best of my theoretical knowledge (I cannot shoot a picture but I have long term friends (since adolescence) who are artists in the world of photography), cell phones are not yet the best cameras or video cameras. You still need separate devices. Sure, you can shoot pictures with your cell phone, but if you are really seriously into photography, you will need a separate device that is optimized for delivering best results while not at the same time ringing and texting.

So if it is so damn difficult to come up with a universal device, it should be much MORE difficult to come up with a universal partner who would meet all of our needs across lifetime.

In other words, people might tend to be non-monogamous (however defined does not matter very much) not because they follow rudimentary instincts or lack intelligence, but rather because they are very complex and human relationships are complex.

So while I see that an inquiry into the world of animals might to some degree be helpful or at least curious, but still we are more complex than even primates. We are more complex than both primates and cell phones.

Or, and the tablet/PC/Mac etc. choices. Nobody has yet come up with anything that would work best in serving all of our needs at once.

Still, there are benefits to monogamy (serial or lifetime, as you wish). Say,

I definitely see the benefits of unprotected sex. There is a benefit of simplicity (clarity as to paternity, clarity as to the succession of legal rights and property rights upon death), and many other benefits to monogamy, but non-monogamy has its own benefits, so there is no BEST or RIGHT way to live, just as macs are not necessarily better than PC's unless you believe that they are.