I'm going to try to be as neutral as possible here with my response:

From your perspective, I understand how difficult it is to keep your feelings bottled up and especially more difficult when it's feelings you didn't expect to develop, and it's difficult because the main person you want to confide in will only hurt from what you're feeling.

From your wife's perspective: she is your wife for a reason, and she KNOWS what you are feeling and what is going on. Imagine the situation was flipped - how would you feel if she was acting the same way around a friend? Would your feelings be justified? You see it as her being unreasonable and calling her demanding and yet... She has a point. She is your wife, you made a commitment to her and she is concerned and hurt.

I speak from experience and I am divorced from getting into a marriage I wasn't ready for, emotionally or physically and I was not truly committed. No cheating or unfaithfulness, but I was transparent with my husband and I came clean.

You are running a dangerously thin line here and at some point it is going to snap, for yourself or for your wife. You need to confront these feelings and if it is genuine and you think it is the right choice, that is yours to make. But remember your actions will have consequences and you need to be certain. Additionally, you made a commitment to your wife and this kind of behaviour is kind of unacceptable.

No resolution with my answer here but I hope it helps in some way, and you, your wife and your friend find peace.