can someone explain Luckiest Girl Alive to me? *spoilers*

[chumbler]

I've just finished it and did enjoy it but I don't get why she was "acting" to get Luke to love her just to leave him anyway? she says things like how she acts "kooky" for him. why leave him on their wedding day? what did she mean "this isn't what'll ruin our wedding?" just that she's going to leave him? why make a fuss about wanting the wedding filmed when this is left out of the documentary in the end anyway? I just don't get it!!

I thought that getting the confession and being believed finally gave her the confidence to be 'her'. Luke was never supportive and was very dismissive of what she had been through. Having the confession finally gave her the confidence to be herself.

that makes sense, thanks. but why go ahead with the wedding? she knew he'd broken the picture before then. (also why hide the shells under the sink? I thought that was a bit silly!)