When are friends allowed (in general)? When are new friends allowed... is it only if they are the same gender?
Considering how you feel, how you get your ego fed and your general sense of needing more than your wife for romantic stimulation while labeling it "friendship", I'd have to say that to keep your marriage sacred, you simply can't have new "friends".
IMO, by definition, friends aren't defined as those you flirt with to feed your ego. You might call that class of women "friends" to differentiate them from women you have regular sex with, are married to, or are dating - but to me the word "friend" can't be used to describe what you say you want.
The line between fidelity to your family and infidelity is crossed in your (our, anyone's) mind and heart long before it's crossed physically or verbally. In your case, it sounds as if you live on the "infidelity" side of the line in your mind and heart, and are just physically stopping yourself from crossing it in the final sense, through sheer force of will. Of course there's no amount of time that can pass that will make that safe in your marriage unless the mind/heart become faithful by choice. It's a "dry drunk" scenario. Still operating on the same principles, but refraining from acting on the principles for as long as you can hold out. And that's not at all a safe place for a spouse with more traditional views of monogamy and fidelity.
Also, I don't believe your wife sounds paranoid at all, simply realistic. She knows you. My guess is she knew this about you well before you were able to articulate it yourself. You simply don't believe what most of us here consider "infidelity" is wrong. Since you don't believe it's wrong then you won't change it, and because it's clearly incompatible with a healthy marriage to your current BW then my guess is you will go back and forth as you have been, achieving this status quo in which you continue to force yourself to be faithful, resentfully, while your wife waits for the other shoe to drop.