I think whenever you add more than a token sex scene it is automatically labeled as erotica. It is our Victorian society that forces such labels. Where your book would be labeled erotica or even porn here, in Europe it would probably still be a just a ghost story. Go figure.
I don't agree with this. I have read many novels, different genres, that have more than one sex scene, and they were not considered erotica. Depends on how integral the sex is to the plot, and how explicit the scenes are.