It sounds as if sex is not the only reason for your discontent...it appears that the relationship has become more of a companionship and, because he is a good man, you stay out of guilt...or maybe even fear of change. I would ask again about therapy because 24 years together is not something to throw away...even if you have to find the therapist and make the appointments, I'd say a few months of counseling might convince you that you've done all that you can do...if this doesn't work, and you feel as if you could be happy out on your own, it might be time to move to the next chapter of your life. He sounds depressed but there is no need for you to sink into the hole next to him...why should you have to fight every day to keep your life bright and cheerful? Being alone after 24 years would be very difficult...but, maybe waking up ten years from now in the same place would be even worse. I wish you much luck in your decision. You sounds active and outgoing...don't let this relationship take that away from you.