It sounds like you've talked to your wife about this, since you've suggested therapy, so does she have any other suggestions? Have you told her that it is making you unhappy? Ask her if she has alternate suggestions to therapy and make it clear that you do want to work together toward a solution.

Also, although I'm not a therapist myself, I am a strong supporter of therapists having therapists. From my understanding (and perhaps some of our therapist experts can weigh in here), most therapists do have therapists of their own. I wonder if perhaps exploring why she is so resistant might be a starting point?

Jim, sometimes therapists have difficulty accepting that they too could benefit from some therapy. Other times, they may be concerned about what others in their field might think if they knew she was in therapy. Either way, it sounds as if you would benefit from addressing it. Perhaps the way to go would be to start by reading some material on the topic. I would recommend the book Passionate Marriage by David Schnarch. This speaks about the difference in desire, with some psychological reasoning as to why this arises, and some ways to work towards a solution. It may also appeal to her as a therapist to think about it for herself first, then address with you. Good luck and thanks for posting this question.

Another great book on this topic is Esther Perel's "Mating in Captivity."

I wonder if you have to wait for her, perhaps starting therapy first then inviting her to come along may help. Her seeing that you are serious about it may nudge her in the right direction. Make sure you are clear why you are going: the relationship is starting to feel more like a friendship and you are (rightfully) worried.