Lots of raw honesty in this thread. Maybe THIS is the club that none of us wanted to join.
Atrophy, yes. Mine can also almost disappear in underwear. I also had a radical prostatectomy, but mine was nine years ago. I was already experiencing some ED before then, treated with viagra, and I was aware that permanent and complete ED was a risk factor after surgery. Happily, I felt some nocturnal stirrings while I was still in hospital, and even though it hurt with the catheter in place, it gave me a lot of confidence. But over the years things just got worse and worse. I was needing stronger and stronger doses of V, but it gave me horrible side effects like the feeling that my head (the one on my shoulders) was about to explode, and I couldn't handle it.
I don't want to go into detail about what happened subsequently, but I did try other methods (Caverject) for a while, but certain events and circumstances since then have meant that the fire is well and truly out. Libido is almost zero now too.
Up until last year I was still able to pleasure myself occasionally even if mostly flaccid, but I also have nothing but numbness down there now most of the time. I suspect that I have experienced some damage to my pudendal nerve from a separate procedure I underwent last year. That procedure dealt with an issue that originated from my prostate cancer. The best I can hope for now is to edge, but it is very difficult to even reach that stage, and there is nothing after that at all.
My wife and I are good. Nothing is expected, her libido is low too, but I am still able to pleasure her in a variety of different ways which we do every now and then, and that makes me happy too.