Originally Posted by BlackUnicorn
The idea of polyfi removes the possibility of your partner bringing along someone new you don't like, or someone who will threaten your position.
It would also remove the possibility of your partner bringing something along that will threaten your health. It stands to reason if you can manage to get the image and reality of polyfidelity to aline that you would receive all the corollary benefits of monofidelity.(I thought I would make up some more words since language has been such a hot topic lately)