Tony, I can remember even in my 30's going through long periods between girlfriends and not feeling capable as well. Some men, including myself are just not inclined to objectify this experience. When I did run into relationships where we shared a respect and mutual understanding, those issues magically disappeared. Now at nearly 62, Ive been in a wonderful relationship for 11 years and still have a great sex life with no need for the usual enhancers.
Don't give up. I have also had friends go through this experience and regardless what the Doctors tell you, there are solutions. There are also new medicines on the horizon that no longer have the side affects that you describe.
Do some research and above all, don't give up...