So basically, it is one of those situations where no perfect definition can exist.
e-rot-ic:
from the Greek eros 
: of or arousing sexual feelings or desires, amatory
The very word is derived from "love" - and to me (and this is apparently where we differ wildly) it's the
love between Lois and Clark that I want to read about. Sex for the sake of sex can be found on countless web sites. I'm here for the characters and the deeper meaning behind the action when things turn amorous. I've read the stories you mentioned by Sheila and Wendy and the reason why they resonated for me is precisely because underneath the erotica was their love for each other.
