Love may not be finite but our ability to handle the consequences of it are I think. Maybe you, who seem to be one of most infinitely loving people I know are banging up against the finite.
I don't think that is necessarily any more polymono than polypoly. Is it not about acceptance?
Some of the deepest wisdom I have come across on poly mono is on the "Living polymono" group at yahoo. That's not the one I'm always recommending for monos but a kind of sibling group for polys with mono partners. If you're really feeling stuck it might be worthwhile joining for some fresh perspective from people who do it very well.