... and it is not a romantic movie.
What I got out of this story is a young man who is sinking fast into mental illness and self delusion. Ben cannot define when he is awake from when he is asleep. It happens so much in this movie even the viewer falls into this reality vs. not reality trap.
His fiancé even states he becomes insecure after every decision he makes. His mother is a psychotherapist, his fiancé's father is a psychotherapist and Ben studied to be one. Yet he is his worst patient because he believes that Nadia is real - we the viewer are never really told she is real - maybe his first meeting her was just a dream. When Ben is with Nadia the colors change in the setting.
When Ben finally finds Nadia his real self and his dream self are indecipherable by himself and the viewer. Therefore I believe this movie is more about mental illness than romance.