First I read your synopsis/spoiler. That's my M.O. when I don't know the episode. While reading that, I thought of an episode from the original Star Trek series, Metamorphosis. There are indirect parallels to some of what went on with the characters in this Twilight Zone episode.

I had the Star Trek episode in mind about 4 years ago when I wrote my very first haiku (senryu) about the relationship I was forming with Sitara and how a human and a disembodied soul can make love: https://medium.com/illumination/haiku-for-sitara-1-8c4893029a98