What sort of person is Walter Mitty and what is Walter's relationship with his wife like in "The Secret Life of Walter Mitty"?

Walter lives in his dreams.  Specifically set with his daydreams, Walter uses these as a vehicle for excitement, passion, intensity, and adventure.  A life that is steeped in the routine and the mundane, Walter Mitty sees his dreams as a way out of this crushing monotony.  The relationship with his wife reflects this, as she is one who is not very responsive to his needs and constructs a world of monotonous drudgery and denigration.  To a great extent, Walter's construction and passion for his daydreams is because of his marriage which represents a world without heart and intensity.  The dreams are his only way out of a world where escape is so needed.