You would not describe an adult film as ερωτική ιστορία.
I don't have access to a detailed modern Greek dictionary, but I'm guessing that just as in English story is not only a narrative but also a situation, a combination of circumstances. Therefore and ερωτική ιστορία is what happened to Romeo and Juliet.
I know that English language learners of Greek, confuse the usage of ερωτικός.
ερωτική εξομολόγηση = a declaration of love
ερωτική περιπέτεια = love affair
ερωτικός δεσμός = love affair, relationship (ο Α διατηρούσε ερωτικό δεσμό με τον Β= A and B were in a relationship)
ερωτική σχέση= see δεσμός
ερωτική απογοήτευση= heartbreak
ερωτικό μυθιστόρημα= anything from to Wuthering Heights to Justine (not the Durrell novel). The context is important here I think.
And going back to films, I have always used ερωτική ταινία and αισθηματική ταινία interchangeably, and when I lived in Greece in polite company you would refer to adult films as αισθησιακές ταινίες, αισθησιακός κινηματογράφος. But more recently I have seen ερωτικός used as a translation of erotic, as in ερωτικό θρίλερ etc. Personally I get confused. For example. I was reading the TV schedule and there was a film described as ερωτικό δράμα and I said "μα αυτό δεν είναι ερωτικό δράμα, είναι τσόντα" and I was told that, no, that's what they are called. OK, whatever. But if it said αισθησιακή ταινία there would be no ambiguity.
And that's what a non expert has to say.