It is a type of movie where people will either rate it 5* or 1*. Can't blame both of them as its subject is like that. The writing is intense. While it seems slow but actually it helps on building the movie.
Acting wise - it is Deepika's movie from the start to end. She totally aces it. The other characters revolve around her perfectly. Shakun Batra's movies focus on people and relationships and they are effectively brought out well.
While the negative reviews should be appreciated, few reviews question Deepika's choices/intimate scenes etc. Hope the movie is reviewed on its cinematic reasons and not on our prejudices based on culture, impact on current generation etc. The movie is based on affairs/extra marital relationships so if that is not to ones liking than the movie can be ignored.