I gave up trying to categorize my marriage a while ago.
She's definitely closer to "poly" than I am in that she actively courts close personal relationships with other men, whereas I'm not really wired to get that close with anyone (male or female) other than her. But even as she develops those relationships, there's a gulf between what she develops with them and what we have together (a fact I have finally learned to take for granted - in the good "I trust her implicitly" way, not the bad "I take her for granted and neglect my end of the relationship" way). When jealousy was an issue for me, it was always on the emotional rather than the physical side.
I am definitely not poly in the emotional realm. She's the one. I can't imagine having that close of a connection with anyone else, let alone maintaining it. If I think about it I suppose there's still a tiny lurking desire for her to have a similar disposition, only wanting to have deeper connections with ME...but that voice is utterly drowned out by the joy we've BOTH found in the freedom afforded by accepting what each other needs.
That's not to say I am closed off and have no emotional connections with other friends. It's just not something I actively seek out. It has to be that rare person and takes time. And even among my closest friends, it only goes so far as I just don't have the capacity to maintain that. It's about the only form of jealousy remaining in our relationship - I am occasionally jealous of her ability be that open with people.