I've never actively dated or looked for a partner, ever. That doesn't make me not poly, in my opinion. Being poly just means I have the ability to love more than one person at a time.
I guess I'm a bit different from you in that when I was in "forced" monogamy I was feeling trapped. However I have lived happily monogamously, as long as I knew I had the freedom to pursue my feelings if I were to fall in love with someone else. Right now I have only one partner, and I'm not looking for anyone (as I said, I never have) yet I don't feel "not-poly".
However, if you really can be happy either way equally, you might be the "bi" equivalent of relationship orientation: poly or mono, both work. I'm not sure if there is a term for that.