Young man, who is poor, falls in love with girl from rich family. They get married and he is easily accepted by her family. He then falls in love with outside girl, with who he sleeps and she becomes pregnant. Then he realises that his life will be ruined if anyone finds out, so he takes hunting gun from his father in law and want to kill his lover. The plot is in UK, I think, they all wear posh clothes and play tennis.

Match Point. 2005