Sexual disfunction for both guys and girls has a lot to do with what is going on in your head...although guys are a lot more visual than girls, you too can get psyched out due to anxiety and stress (a lot of us girls lose our desire due to stress of pouch leakage, image problems etc)...throw pouch surgery into the mix and even if no one has touched any nerves or other 'guy parts' you can walk away with problems...
Setting aside functional problems, I am sure that a lot of you suffer from performance anxiety due to 1 incident. If you try and fail the first time out you get stressed or panic the next time and it can become a cycle (not talking about the 'real' functional problems here)...when speaking with my doctors and a few of my clients (I am a coach) I found out that this a rather common problem for guys. My doc said to 'break the psycological cycle' is the only way to get past it for men...he prescribes a short run of a viagra-like med for no more than 3 goes (does not want the patient to become psycologically hooked on it believing that that is the only way to make it work). He says that it usually does the trick. Occasionally talk therapy helps too...
Don't forget that you guys depend a lot on your pelvic & abdominal muscles for things to work well and if you have atrophied or weak muscles you are going to have problems there too...start working on your keigels to reinforce those muscles even if you can not yet do crunches or other abs...
ps...and this is a girls opinion here...sex is supposed to be fun and not a serious affair...so go back to having fun, make it about pleasure and joy and less about performance...and things may just go back to normal on their own.
Sharon