I agree with @JPBenedetto on this. Of course lol =p
Yeah. Sometimes you just spend so much effort into something and then you realize.... it's not worth it. They're not worth it. I don't know the whole back story, as I haven't seen the movie (yet), but she's with another guy there. And then he does that. Goes through all the effort to buy those supplies, figure out what he wants to write, wrote and poured out his heart in those letters, probably messed up a few times, cut out and paste the pictures. Then had the courage to walk to that place and act out what he had probably envisioned a thousand plus times in his head.
and then she kissed him. While she is with the other guy.
Then she ran back to the other guy.
It's one of those moments where you take a step back and look at how stupid you're being. How you're putting so much into something... nay, someONE who isn't worth your time and effort.
So I think he was able to start moving on after that. Without seeing the movie and just speaking off of personal experience, I think a part of him had already (or started to) moved on and he was on one last thread of hope. I doubt he would've been happy with her anyways at this point, even if they did end up together. Even if it's Keira Knightley <3
I like to think he moved on, and couldn't do that until he came to grips with (and finally expressed) his feelings. It's much easier to transcend...once you've purged yourself of all the pent up emotional energy. Just my humble opinion...