Regarding the single case, she is 36 so hardly a hot piece of treasure...and generally its not the top dogs that hit on such old women.
Personally I find it hard to get turned on from post wall women, let alone get intimate with them.
In my opinion and experience, most issues happened when the girl was either nothing special in terms of looks or when the girl stressed the hell out of me.
I never had erection problems but I had the shot&run problem which is when your body wants to drop your load asap then leave.
This basially happened with most girls that annoyed me or stressed me, its like my brain wants to cvm to get a return out of the effort but nothing more with them.
Never had any problem with hot girls even in stressful environments if the girl had great look and didnt create problems, I got plenty of action in my own office with my boss near-by but failed to have decent s3x with annoying girls in the peace of my bedroom.
I recall a night with a girl met in a club, face was nothing special but the body was amazing, fitness model type and a stone hard ass.
Banged her like a jackhammer with no concern at all...no change in hell of that with other less attractive ones.
Also many of us dont realize that men sexuality have a ON/OFF switch, many times Im turned on but after I have to drive 15 min from the club to my home Im no more while women dont have this problem since they are more like a hoven to warm.