I sort of wonder if this isn't going to have some kind of twist like the ghost actually being a manifestation of the husband's repressed emotions. The narration describes the husband as awkward and lacking confidence, with the weird twist that they haven't gone 'all the way' in a year and yet are trying to get pregnant? If he was repressing his desires because he thinks his wife won't be into it (but it turns out she really really is?) it could make sense that it could become some kind of paranormal manifestation. I think it's interesting the ghost, uh, 'interacts' with her primarily when the husband is asleep. (Or pretending to be, since he mentions he heard her moaning.) The ghost also stops when she decides she's not really cheating because the ghost is dead, then makes a point of leaving through the door instead of doing more ghost yoga and floating off.
On the other hand. Maybe this is just a story about having a breakdown after being trapped in a bad relationship. And that much hair in the shower is clearly nothing but a nightmare. I'm also not sure I like the ghost breaking the mirror. Is that circle consent or affirmation? Is the ghost agreeing that she'll be safe with him, or acknowledging that he really is dead so it's not cheating? Either way, it's scary. Why can't he just write something on a fogged-up mirror??