This is probably a foreing movie from the 90s (or 80s)
It's about a writer (novelist maybe) that hooks up with a girl, they have a relationship until he leaves her and she gets kind of mad.
Later on this writer has an accident and becomes paralytic in a wheelchair and the girl comes back with him. He is now in a weelchair and depends on her to live.
The film passes in a train where the writer tells his story to another couple and has flashbacks on the events that happened before.
Also the film contains too much erotism and nudity.
I remember it has a tragic ending, don't know if the writer kills himself, or kills both him and the girl, or the girl kills him.