Years ago when I first read John Irving's The World According to Garp, I was astounded that most of the younger adults with whom I had contact didn't like the book when I loved it. I began to understand that it was an age and experience thing. I experienced somewhat of a déjà vu when reading some of the comments on this site that were clearly written by younger viewers. Fully enjoying Separate Lies is surely an age and experience thing.
In this film the viewer sees a seemingly happy upper middle class couple - he a successful lawyer - she the perfect wife of a successful lawyer. They have a townhouse in London and a home in the country. All's well until there enters the "villain" in the guise of the son of the richest man in the village. This guy appears to be a cad from the word, "Go." He is disdainful of everyone and everything including his own children. In the traditional form of nice guys finishing last, the lawyer's wife engages in an affair with the bounder. You see the lawyer really is a nice guy but with the marriage killing trait of an organized perfectionist. Even though he truly loves her, he is boring his wife to death. The bad boy is far more exciting.
All of this is entangled with the hit-and-run death of a man in the village in which all the facts point to the cad being the driver of the vehicle.
It's easy to determine that this movie doesn't build to a happy ending, however, it does lead to a very satisfying ending in that the man and his wife learn and grow from their experiences and probably will be able to conduct their personal lives in a more successful manner.
Three excellent actors play the main characters in this film, and it is there performances that make the whole thing a pleasure to watch. Tom Wilkinson is perfect as the husband. His portrayal shows us a kind man who has so much control over his emotions that he has lost touch with the world. Emily Watson shows us a woman who has become so trapped in the role of perfect wife that she has almost lost her knowledge of passion. That passion is reborn by the character deftly played by Rupert Everett.
If you have reached that point in life in which you understand that everyone has feet of clay and that everyone - even with the gifts of intelligence and opportunities - makes many many wrong decisions, then you will probably enjoy watching these excellent actors creating the lives of three such people. This is a beautifully acted and directed adult film about realistic adults.