This is from http://thehollywoodinterview.blogspot.com it intrigued me to want to see the movie and read the book. Just thought I'd share.
"The Heart of Me opens on the London of 1934, a bleak time if there ever was one. The first World War has been over for some time but the second one lingers on the horizon. [Olivia] Williams portrays a stiff and proper society woman named Madeleine who is married to the wealthy Ricky (the always great Paul Bettany). When Madeleine's father dies, she and Ricky take in her eccentric bohemian sister Dinah (Helena Bonham Carter). Soon Ricky and Dinah are drawn to each other like star-crossed magnets and find themselves in a disastrous affair. Madeleine wants it to stop of course, but not so much because she loves Ricky as because she wants her life to maintain its status quo. At first glance, it seems obvious where this story is headed: Madeleine is the evil wife who prevents true love from blossoming. But what is so defining about the film, directed by Thaddeus O'Sullivan and deftly adapted by screenwriter Lucinda Coxon from the Rosamond Lehmann novel The Echoing Grove, is that there are no “good” or “bad” characters in the story. Madeleine takes some devious steps to disrupt the romance, but you will also come away from the film feeling great sympathy for her. The illicit lovers Ricky and Dinah will commit some despicable acts as well, ensuring that you won't necessarily be rooting for their love to succeed. Symbolic of the way the film views humanity is the bracelet that Ricky makes for Dinah - it’s engraved with a line from her favorite Blake poem which reads, "And throughout all eternity, I forgive you, you forgive me." By film's end, all the characters may not have quite forgiven each other, but we the audience will have. Or at the very least, we understand why they did what they did."