Indeed, in a nice and quiet neighborhood, two stories are happening.

Sarah, a "desperate housewife", is attracted to a stay-at-home dad who often comes to the park with his little boy. Both married on their own side, the first to a man who is obsessed with pornography on the internet, the latter to a woman who is obsessed with her job. Those two unhappy married parents are going to find each other and feel intimately linked by their own desperation.
The other "event" is the release of a pedophile. Ronny has some issues concerning his sexuality and is desperate but his mother is here to help him. The problem is that the inhabitants are terrified and pretty unhappy to have a pedophile living in their nice and quiet neighborhood full of children.
The movie was just so right in the actors'performance and situations. Everything looked pretty right to me in the development of the movie except the end concerning our two lovers. And I was in the end touched by Ronny and Larry. I like how things end for the two of them.
Also I really loved the performances of the two main actors, Kate Winslet and Patrick Wilson.
To conclude ,2 hours with mixed feelings and apprehension but in the end satisfied, and touched by the characters.