(written from a Production point of view)
According to the deleted scene 15A from the Star Trek: The Next Generation fourth season episode "Remember Me", Cara Hill was a scientist in the field of exobiology assigned to the USS Enterprise-D in early 2367. She was the wife of Doctor Richard Hill and came aboard with him six months prior to the episode. The script described her as middle-aged. When asked, she did not remember him or even ever having been married, except to her chosen field, and said she had come alone.