This thread has one big red flag on it for me. Maybe because you are not describing yourself as poly? Maybe because all I see us your selfish want to fuck your friend? Sorry, it just doesn't sit well for me. I am glad that you are thinking of others other than yourself (excuse me your cock). At least that is promising.
I hear you when you say this woman is a good friend. I hear you when you say you will just back away if emotions get sticky. I hear you when you say that you just want to fuck ... But what does that say to her? What does that say to your wife about her worth as a sexual woman.
As a woman who has been used in this way, it says, "you are worth nothing to me other than the hole between you legs." presented any other way and it still adds up to that. You want to masterbate in her. Yup, I agree with your wife, watch some porn and you will create less damage. She is your friend. She trusts you, relies on you and appreciates your help where men are concerned. You will likely jepordize all that and add to her lack of self worth and cause her to distrust men.
Your wife is leading the way on this it seems. Fuck her senseless and use it to better your relationship. She sounds just awesome to me. Why wreck it. Why not enhance. That is what my poly is about anyways; enhancing love, and creating more, not creating less and pushing it for a fuck.
That being said; if you had mentioned love in there for one moment! I would have a world of ideas for you, but you haven't and have said you are not interested in poly. I'm sorry, but unless there is some change to your feelings about her then I don't have anything for you.
Anyone want to be friends on Facebook?
Send me your name via PM