The question of mono poly relationships is so broad really. A poly relationship may be continually open to new relationships creating a very fluid dynamic. Other poly relationships may be very closed consisting of three or four people who are committed in a polyfidelous union.
Some dynamics will be more challenging for mono natures to accept and for poly natures to be healthy in. The key is to determine if the relationship is worth getting through the initial work in order to achieve positivity in every one's life and heart.
Drop the labels if you want and just accept that everyone of us is an individual. Every relationship will be shaped according to many aspects of each individual.
Playing the Game of Life with Monopoly rules.
Monogamy might just be in my genes
Poly Events All Over