Yasuru, it seems like your wiring might be different. The good advice to talk to your wife is the first step in learning how to live with that untraditional wiring. Recognize that identifying as poly (even if only to yourself and the wife) takes some adjustment. One of the hardest for her is likely going to be understanding what polyamory is and why it's not cheating (cheating is a mono concept thanks to the one person / all else is cheats mentality). One of the hardest for you is likely trusting the wife enough to open up and admit your feelings.
There is a stubbling block right between thise two points. When you reach out and tell her about your poly thoughts, you're likely to feel a sense of relief. At the same time, your wife just got what may be unexpected news (or may not be, and you're already making progress). That news will be heavy at a time when you might suddenly feel light. Be careful to be mindful of her reactions and needs.
I know that I feel nervous whenever I talk about a new interest with my mono (wife, mother of child). We've been together almost 5 years, and I've been "out" the whole time, but I still get nervous. Just this week she was comforting me because I was sad over something in a poly situation was not being the way I'd like it to be. You at least can point to the fact you've brought this to her before consumating anything. You may even find that your feelings are not news to her (K seems to know as soon as I do if an interest develops--sometimes it seems before I do).