I experienced some of this from the opposite point of view. My husband lost interest in sex and I think it was because his T levels plummeted.
I asked him to go get a check up to see if that was it and if there was anything that could be done about it. He would not go. He seems to have an aversion to doctors. But basically he refused to do anything to fix it. That's what hurt the most, that he would not even consider getting help to bring sex back into our marriage.
You have been asking doctors for help for a long time and sadly had some doctors who just bushed our concerns off.
Apparently your husband does not understand what low T levels do to a person's sex drive. That's his problem. And I don't think you can convince him either since he seems a more than a bit hard headed.
My suggestion is that you do not try to convince him of anything via words. Instead just do what you need to do. Start taking better care of yourself. Do whatever you need to do to get your T levels up. This is not just about sex drive. It's also about your entire mental and physical well being. So work on your own health.
He will see the changes. Then it will be his choice of how he responds to the positive changes in you. It is true that when one spouse changes, it often causes discomfort in the other spouse. So give him time.
I get that you don't want to try counseling. It often does not work. Instead I going to suggest a book that I think will really help you. I like self help books. Unlike counseling, they cut to the chase and teach you things that can help you. Pay special attention to the chapter about introducing change into your marriage. Divorce Busting: A Step-by-Step Approach to Making Your Marriage Loving Again
by Michele Weiner-Davis