I'm in the same situation. I don't believe in living for the sake of someone else, but the thought of the devestation I would leave after my death does bother me. I've read when someone commits suicide, it can spread like a disease. Those closest, their rates of committing suicide skyrockets. My mother has suffered a lot in life and I know if I were to go through with it, she would die. Maybe not physically, but her spirit would be snuffed out forever.
I've no idea what to do, but every day I get a little closer to CTB.