I'm not aware of a commonly used word to mean, exactly, "one who loves ghosts." Then again, the situation doesn't often present itself, so perhaps we should remain open minded enough to accept that such a word may exist. (ideally, would not want to resort to a neologism)
Consider the below on Euripides' play "Helen":
According to this setting, the real Helen never went to Troy, but was swept off by Hera out of spite to Egypt because Hera was unhappy with losing the beauty contest. Euripides further clarifies that the woman Paris was with was not the real Helen at all, she was just a phantasm. The real Helen was in Egypt, still loyal to Menalaus.
And now let us complete the following sentence:
Jeffery Dalhmer was a necrophiliac and Paris was a _______ — albeit the latter took on the appellative unknowingly.
Best Answer
Spectrophilia is sexual attraction to ghosts or sexual arousal by ghosts. It has a Wikipedia page, which notes that although it may not be a genuine paraphilia in psychiatric terms, it is common in myth and legend including the Latin American legend of La Llorona, European myths of incubi and succubi, and the stories of Chinese writer Pu Songling.
See also the question What do you call someone who believes in ghosts?, which has suggestions including ghost-believer, spiritualist, superstitious and apparitionist,