If I wrote the movie it would have ended with Amy realizing that she loves Peter, but he finds out she only agreed to go with him to the wedding that way he could be number 6 and Dan could be 7. Then Peter pretty much tells her to get lost, due to the fact that he is so hurt.
And Amy’s heart is broken because she had to follow that time line and it screwed her over in life.
because that’s how it would have happened in the real world.
I really do love the movie though, and it is supposed to be this happy feel good romance movie so it couldn’t really have a sad ending, but whatever.