Whoa now guys. There's a difference between being able to achieve an erection and losing one/being able to climax. Testosterone and estradiol dictate sex drive, and the the ability to achieve an erection.
However, if you're going soft during intercourse or are unable to ejaculate; I wonder if prolactin isn't a problem. I don't remember, did you have that tested MeanGreen? High prolactin most definitely can lower testosterone too.
I might be overreacting a little, but I'd hate to see you discover later on that you had a pituitary misbehaving instead of it just being a primary-ish hypogonadal problem.