There’s no mention of her in The Last Jedi, but that makes sense considering Luke is a private person in the movie, he has no reason to tell Rey, a stranger, his life story.
If this does turn out to be a real line from the novel, it raises several questions.
We also have to wonder at what point Luke got married and what happened to his wife?
It would be pretty distracting if it were just an off the cuff remark that is never addressed again.