My point is that you can be married and just as alone as before, if you don't find a partner who is compatible with your values and personality. It's good that you are working on yourself, but you must find more to live for than just having a partner. As I said, I expected to be alone my whole life and to just be relying on myself for everything including sex. It's all about attitude.
So you are planning to end your life because you feel you will never have a partner? I disagree with that so strongly. Please seek help by talking to your doctor, a therapist and a good friend or family member. When you were a kid, what did you want to do? Have you achieved it? Why not make some meaning in your life? I am a published fiction writer (short stories) and working towards my dream of publishing a novel. What would YOU like to do? There must be something. Travel, photography, art, music, become a wine connoisseur?? Do you already work in your dream job?
Do you have children? If so, realize they would be devastated by your death. And if not, there are others who would be.