A Little Different Interpretation

Rating: 10/10 (11 January 2015)

I actually interpreted the ending in a way that no one did and I do not want to feel stupid so I would just share my interpretation of the conclusion.
The opening scene showed Amy's husband rubbing her hair saying some words. Now that same scene is also at the end, re acted though and a little different.
But what I concluded from this was that she was only thinking all this up in her mind to get revenge from her husband for cheating with her and nothing actually happened.
We often think of insane plans and executions in our minds that may not be possible so easily in reality. The same type of plan and its execution is shown the movie. I liked this movie because of this interpretation that Fincher was showing just the tensions and secrets of a marriage through this and nothing actually happened. The same is also visualised in the scene where Amy's says,"That's marriage.", in a way that she just wanted to teach a lesson to her husband and everything was normal again.
Do anyone have the same thoughts?