I think it really and truly depends upon what peoPle want. For example, i dont think i could do poly with a partner who lived further than across the street. But, living altogether I can manage two relationships. I personally want to see my partners daily.
But, other people dont mind if they are limited to seeing partners once a week. It is so very individual.
I will say, i do not think its viable if the parties aren't on the same page with their relationship needs.
"Love As Thou Wilt"