Identities, for me, are not permanent. Well, not all of them, anyway. I allow for plenty of fluidity and lots of possibility for change in my life, so when I say I am monoamorous, I generally mean "have been up to this point in my life."
There was that one time when he had me tied up and was in the middle of sexytimes with me when she called...
The patterns exist and are recognizable. They are reinforced by the messages we consume, whether they are generated from the society's large-scale mononormative culture, or the small microcosms of polyamorous subcultures. We internalize and normalize them until we don't even see them anymore.
What if where you are in your life is EXACTLY where you're supposed to be right now? What would that be like, to stop comparing your current location to a perceived end-game?