Hi Berri,
Welcome to the board. Well, from all my reading and from other threads here on the board, it is very very difficult for therapy to make a difference with an N. I think it is a minor miracle you have your N in couples therapy with you.
The reason for saying that is because of the built-in Catch-22 of Nness. Narcissists must undermine ANY threat to the illusion of perfection. You can't even reach them with the promise of improving on a "good" thing, because they believe they are already perfect.
In addition to what others posted on your codependency question, I believe another characteristic of C is focusing all one's energy on getting another to change their behavior. Another approach for you to consider is to get individual therapy to help you cope with your partner's narcissism, to help you discover the hooks inside yourself that get caught up in any problematic behavior. Another idea that others here have tried is to schedule individual appts or phone calls with the T to see what their read really is on their partner and on the relationship. Some Ts recognize the narcissism and do not confront the N with it directly. If they did, that would be the end of therapy and they are hoping to work towards it gradually.
Only one author espouses hitting the (usually male) N directly between the eyes: Terrence Real. You may want to look into two books by him. I Don't Want to Talk About It (about male depression and includes a chapter on N) and How Can I Get Through To You?
Good luck to you. Seeker