Poly and your relationship are entwined. I don't think they are separate at all, just that you seem to be consumed with your relationship being mono one way or poly the other. Really, in the end, there is no difference other than the people being in your life "getting" the whole poly thing and being involved with others themselves.
It sounds like poly means dating and potential partners to the two of you. I would suggest going and finding like minded friends. Build community around you and see how it goes with your new friends. Find a poly group to hang out with. If there isn't one, create it. Ask people for coffee and make it a friend thing rather than making your meet ups a date thing.
To me, after 17 years, poly is a way of life built up over time and positive interactions with others. So many people around me are friends rather than lovers. Its made me feel grounded in something more than a slew of other relationships other than the husband I married.