Life guarantees no one a love/sex/romance partner. No matter how poly you were born so how much of a way you were born is it really?
There are people who want only one partner but cannot find that right one partner.
And if one could be born poly, and that means they are unable to prevent who they fall in love with, wouldn't any restriction on how many be unrealistic? To even tell someone "oh no, you and them, and once a year that one too is ALL I'm ever going to have time and/or need of"?
It would seem to me that if being poly were intrinsic to living, you would be able to assure no one of anything if they are to be in a relationship with you.
Dunno, it feels like a perpetual weighing of pros and cons of what life affords you to me.