It's The Astronaut's Wife with the sexes reversed, the story of a returning astronaut altered by some experience in space. Back in the 60s, there was an Outer Limits episode called "Cold Hands, Warm Heart" that told the same story. It's appeared in written fiction, such as one story Samuel R. Delaney wrote...arrgh, I can't remember the title. There's not one original thing in Extant, but I did like the show's quiet approach to telling the story instead of relying on F/X and action sequences.