First off, I don't see any problems with the pacing, the visuals, or the music in the movie. All were fine and in fact, although the ending felt a bit rushed, it was not just meaningful but also artistic without being pretentious.
I agree, however, with some of the reviewers that it more falls into the drama genre than thriller. I have a brief moment of disappointment with good flicks that are categorized wrong, but that's about it.
Now... My character analysis is somewhere between the spectrum of views from the reviewers.
The movie does not clearly hint at any possibility that Clarke's character specifically went out to find someone permanently vulnerable to marry, due to a handicap. When you extrapolate the characters into the past, perhaps some of the audience would say that is very likely. Understandably so, as there are many people who actually feel so insecure as to purposely marry totally dependent partners.
The problem in the movie is, though, Lively's character doesn't waste time to confirm her husband's fears, and denies it when confronted.
It would be only natural for her to change her looks following the operation- she had to see herself first to know what she wanted to look like.
That was not what troubled the husband. It could have been, in other cases, but the movie tells us that it is not.
What critically troubled the husband was that scene on the train that he kept replaying, closing up on his wife's face as she thought no one was watching.
Also the realizations: 1. she lied about the man in the park 2. she said she was pregnant, without knowing her husband was sterile.
Whereas he could confront her and file a divorce or give her a second chance, the husband hatched a wicked plan to have her blind self back, failing to accept the fact that newly gained eyesight would make one discover more about oneself and have preferences with things one had no way of deciding before. As Gina said: "we don't know who me is." This was the problem. The husband could only get to know this new wife as fast as she could get to know more of herself. This problem was not mutually shared, as the wife had understandably welcomed the changes with delight.
Said another way, changes happen faster than the husband is able to let sink in and upon realizing that he is losing his wife, he tries to reverse the process back to when he knows she would need him, therefore would keep him, as if he can make her unsee things, rewind time. So he tries to actually blind her. That is how mentally sick he has become.
As the wife is singing this song on stage from a time when she was blind and all she saw was him, and staring straight in his eyes all the time... there's this silent conversation via exchanges of gazes of how she used to love him, how she could still see and knew what he had been up to, and how he ruined it all. He gets the messages, walks out on her and jumps in his car, and, absorbed in a very emotionally intense session of self-introspection and judgment while driving, ends up in a fatal accident.
A life ends as a new one begins. Things move on, one way or another. If he had thought about it before the operation he could prepare and therefore grant himself "the serenity to accept the things he cannot change".
I loved almost everything about the movie without the need to root for either of these two characters who had become very realistically unlikable as the movie proceeded. I respect this in a movie. A cold but sincere little flick.