'The Deep Blue Sea' is set on the 50s and it starts with the main character (Hester Collyer, wife of a much older High Court judge Sir William Collyer) trying to commit suicide. Then, it goes back to the moment she meets Freddie Page, a young ex RAF pilot whose vitality and desire to live attracts her. With him, she will experience a sexual awakening and a truly passionate love. However, Freddie doesn't love her the same way. This will lead Hester to her suicide attempt.
From my point of view, Freddie Page is not just the bad guy, as people usually picture him. He is a very complicated character. He was in WWII, where he saw his friends die but he survived and he is still caught up in the past. Besides, he is searching for that mix of fear and thrill that he felt when he was in the war and he didn't know if he was going to survive or not. And that is why he decides to leave when he knew of Hester's suicide attempt, because he is trying so hard to enjoy life and to not get attached with someone else feelings that he can't cope with it.
A reason why I love this movie is the capacity of the director (Terence Davies) to capture the emotions of each character. For example, when Hester meets Freddie, Hester is surrounded by dark while all the light is directed to Freddie. This represent how Hester sees Freddie as her salvation to her unhappy marriage. Each scene is perfectly calculated. You have the feeling of watching a play in a theater. The other reason is that I love Rachel Weisz (Hester), Tom hiddleston (Freddie) and the brilliant Simon Russell Beale (William, Hester's husband).
In a nutshell, if you like British movies I would totally recommend this one to you. Some people may think that its pace is slow, but The Deep Blue Sea is totally worth it.