The others have gave plenty of useful food for thought already, so I won't say too much. Just welcome you to our forum.
I would say it's okay to take it at an easy pace with the communication, but like the others said just don't expect your wife to know something (or connect the dots) until you spell it right out. Polyamory's too big of a topic to risk any potential unclarity.
As for how you "know you're poly," I'm more from the school of thought that most people are probably potentially monogamous to some extent, and potentially polyamorous to some extent. It's a slider type of a situation. So you know you're probably somewhat poly, but you don't know exactly how much. Mainly for now you know that you're poly-curious.
Since it's hard to be 100% certain about these things, you just have to be honest with your wife about what you do know, and admit that you're still in the process of figuring out the rest.
Hope I didn't actually add to the confusion ... Those are just my initial thoughts.
Anyway, glad to have you aboard.
Love means never having to say, "Put down that meat cleaver!"