I think nerves take time to heal, and in my case about two plus years. I am currently 3 1/2 yrs post op and I am almost back to pre surgery sexual arousal condition.
I was very very lucky in that I was able to get a 100% rock solid erection within days of the catheter being removed, and withou the aid of drugs, BUT, only with a lot of manual stimulation. Visual stimulation did nothing for me right after my surgery. I could look at naked women 24/7 and felt absolutely nothing, not even a tingle. But as soon as some manual stimulation was applied, the erection came quick and hard. The second the manual stimuli stopped, so did the erection.
This went on for about two yrs then in the about the second year post op, I started noticing that I was waking up every morning with a rock solid morning erection like I use to prior to surgery. So solid was the erection, I could hang a towel over it. The only problem is that within a minuit of getting up, the erection fades if no manual stimuli is applied.
Now at 3 1/2 yrs post op, I can actually get about 25% erections with just visual and mental stimulation. Yes, now looking at a naked women and thinking sexual thoughts, I can actually feel tingling in the penis like it is trying to become erect. I still need the manual stimuli go get the full erection, but now not as much as before.
So I really believe that nerves take time to heal, so don't loose hope.