So... maybe putting that value of love question aside for a while, and assuming that different types of love each have their own value, there are elements of our society that desire/need/want more than one romantic/sexual love in their lives, and there are others that don't. They need a shorthand way to describe this, as is the requirement of language. What would you propose they use to make this distinction?
Hmmm - I'm not convinced that there is a distinction to be made (or at least, not one).
There are some people who only want one romantic/sexual love in their lives and who will drop other relationships when they have that. One of my friends has a pal like that - when the pal is single, they spend lots of time together and are very close. When she's with somebody they don't - she places her full attention on her romantic love. I try to avoid being friends with people like that!
There are some people who want only one romantic/sexual love and who will have close friendships with lots of other people. Others will have close friendships but not with the gender they attracted to. Others might have close friendships but only with long-term friends and making new friends are out of the question.
Some might have one romantic love but be closer to a platonic friend. Or closer to their dog. Or closer to a group of friends.
Same really with people who have more than one romantic love.
And these might change for the same person over time.
I've spent time where I've had more than one romantic/sexual love but was emotionally much closer to a platonic friend (that's been a bit of a pattern for me and tended to suit me very well I think).
Then I had a single romantic/sexual love and almost no platonic friends (made me miserable, sadly. I say sadly because my love is an amazing person).
Now I have a single romantic/sexual love who I am emotionally attached to and lots of platonic friends some of whom are emotionally close to me and some of whom are less so.
If I'm asked, what I say to people now is that for the moment, I'm having sex only with my love as we have stuff we need to sort out. And that maybe that'll change in the future. And that if they want to be platonic friends, I'd be very happy about it.
Doesn't take that long to say and describes the situation much more accurately than saying we are monogamous or polyamorous - neither label really fits.
And of course, the other good thing about being a bit more accurate in describing the situation is that it lessens (a bit) the risk of misunderstanding.
Thanks so much for the thought provoking replies.