It might not be the feet that are the issue but the shoes. Sweat soaks into leather or canvas, or other materials, and then starts to smell.
I once dated someone who didn't wear socks, ever! His shoes stank up the house! My mom had to banish his shoes to the front or back porch. Once his feet had been out of the shoes for a half hour or so there was no odor.
I once had a pair of shoes that smelled, which caused my feet to smell. Got rid of the shoes, got rid of the smell.
It hasn't been a deal breaker although my stinky shoes almost were.
There are as many ways to do polyamory as there are people practicing it!