I waffled on this one. In general I view mono vs. poly as describing relationships not people. On the other hand if one is open to more than one romantic relationship at a time, even if they are in NO relationships currently, then I would still think of them as "poly". (Kind of like I think someone can be gay/straight/bi even if they are currently celibate).
I picked moderately poly for me - I'm happy in my current poly relationship but for long stretches of my life I was just with MrS and was perfectly happy with that as well (open to but not actively seeking other relationships).
Me: poly bi female, in an "open-but-not-looking" Vee-plus with -
MrS: hetero polyflexible male, live-in husband (23+ yrs)
Dude: hetero poly male, live-in boyfriend (4+ yrs) and MrS's best friend
Lotus: poly bi married female, "it's complicated" relationships with Dude/JaneQ/MrS (1+ years)
+ "others" = FBs, FWBs, lover-friends, platonic G/BFs, boytoys, etc.
My poly blogs here:
The Journey of JaneQSmythe
The Notebook of JaneQSmythe