Have you been to a fertility specialist?
My Df had low sperm count and lazy sperm and the FS did tests to see exactly why and in our case we were lucky because it was something that was treatable.
With you have you had any blood tests? I remember I had one on a certain day of my cycle just to make sure I was O.
As another poster suggested fertilty friend is a great website to use to moniter your temps and your CM.