My understanding of the terms is that polyamory is multiple relationships with commitments

I have encountered a sufficiently large number of people who use use "polyamory" as explicitly implying no commitments that 'polyfidelity' ends up being a more accurate descriptor in terms of the root words.

Given that calling folks out on the important distinctions between polyamory and polyfuckery is often not reacted to well, just using (even if slightly incorrectly) another 'poly'-prefixed word is easier.