Funny, I agree with both ColorsWolf AND you
I do agree that there's no need to shove this in the wife's face at the very first, but I also can see where Colors is coming from when you encourage the OP to say things like,
"Hon, I told you I love her. But she's my friend, nothing is going to come of it and I want to let it go and just BE friends. Keeping bringing it up is not helping me to let it go. How can I help YOU let it go?"
Really, the OP thinks that something WILL happen, or this issue would never have come up. Encouraging the wife to live in self-denial, well, some people can handle that, but others truly start living in a fantasy world and it will only be more painful when the reality starts crashing down.
Perhaps the OP could say something along the lines of, "I don't know what will happen, but I do have feelings for this other woman (avoid saying "love" perhaps?) I will always love you, but this person is starting to be very important to me. But I do understand that maybe you just don't want to talk about her for now, so I won't bring it up unless you do." That way she's being gently, but she's also not lying.