How many of your partners are shared with other men? Alternately, if you're female, how many male partners do you have?
There is one unique alternative here and that's the landscape of emotional needs is somehow much more diverse than the landscape of physical needs. Then it would make sense to maximize among many partners as it's unlikely that a single individual can have all the skills necessary to satisfy a long list of independent needs.
Although even then I'm skeptical, the polyamorous couples I've seen don't seem to last long (~5 years) and eventually the male chooses or vice versa.
There is one unique alternative here and that's the landscape of emotional needs is somehow much more diverse than the landscape of physical needs. Then it would make sense to maximize among many partners as it's unlikely that a single individual can have all the skills necessary to satisfy a long list of independent needs.
Although even then I'm skeptical, the polyamorous couples I've seen don't seem to last long (~5 years) and eventually the male chooses or vice versa.