Maybe instead of assuming that your W is acting because of her friend visiting, why not take it as she has changed. Assume the best instead of the worst. This way you will find it a little easier to be nicer with her and it might get the ball rolling towards an improvement in your over all marriage. Why not? Also, remember that positive reinforcement of a behavior you like does wonders. Reward her with an unexpected thank you or hug or flowers when she makes you happy. You could set the examples now for later. What I mean is that if she does "change back" after her friend leaves, she is more apt to recognize her behavioral difference if you attach it to something memorable such as flowers for a specific behavior. You could then start a convo with her going something like, "hey honey, I just wanted to say again, how wonderful it was last month when you -------. It made me feel closer to you and more in love. This is why I felt compelled to get you flowers because I knew how much you like flowers. Is there something I could be doing differently to make you feel a similar way?"
