Hart Susan Hart 
Ghost Mariner — the Warmth of the Fireplace Series, Number Four [EPUB ebook] 

The Ghost Mariner is about a woman who wakes up in bed in a strange location, sweating with fever. She sees the outline of a man as he comes closer and then welcomes him to her bed. After they make love, he tells her he’s the ghost of a long-go sea captain and that he will have to leave soon. She falls back to sleep then wakes up in a modern hospital room where she hopes she can get some kind of an answer as to what has happened to her.