It can be complicated. Society doesn't really legitimize polyamorous relationships, this is true. It also doesn't legitimize gay relationships, for that matter, in most places. Being different can be very very hard. For me, I would much rather be true to who I am, which is pretty different, than to pretend I'm something I'm not.
It's also okay (totally) to feel that you're not wired with polyamory as a "need."
Besides, I love being with my primary, and knowing we are poly, we can do things like flirt, and openly check out hotties on the street, and do sexting messaging if we feel like it, or talk freely about sex and kink with anyone we want, look at all the porn we want, go to burlesque shows, cuddle, things like that, with no jealousy.
D and my relationship was like this from the beginning, even though we were only with each other for about two and a half years while we (mostly me) worked on general stability and communication issues. I think the spirit of our relationship has always been poly, even though it was in a monogamy shell for a while. Which is cool too.
Both of us are just more wired to want that "more" thing. Not everyone feels that, go with whatever makes you happy.