The ending has to be the most brutal scene in the whole movie. It would seem that Christian had been driven by some compulsion to punish Ana. He forces her to strip and bend over and then begins to hit her with a belt. Making her count the blows as they land. She starts out softly counting one, then two she begins to sob with tears streaming. Her voice never rises, and she seems to accept the physical pain that he is inflicting on her. When she finally reaches 6, the punishment ends. She then rushes to get up and covers herself in humiliation and embarrassment. She is staring in horror at the man she feels that she loves.
She then asked if that gave him pleasure.
If you actually take a second to look at the bible, the number 6 represents man and their weakness, imperfections, and his fall. It is strangely fitting that Christian chose the amount of hits that she got to 6. It is this action that shows that this is what happens when a man tries to fix his brokenness. It has shattered Eden and Eve has covered herself in shame.
This is why she ends up leaving him.
Fifty Shades of Grey actually gives us two broken people to find comfort in each other. This is actually a love story, but any love story that starts out twisted like this, could be said that it won’t last that long.