Searching for "the one" or is this a notion of society?

I was inspired to write tonight after seeing "(500) Days of Summer". This movie is not a romantic comedy by any means, so I thought, but is a boy meets girl, boy falls in love, girl doesn't, kind of movie. A little corny, and at times frustrating, it was about the struggles of finding that special person and true love. A boy falls hard for the girl, Summer, who doesn't fall hard for him and quite frankly just wants casual sex. This movie moved me to wonder, is there just one person meant for you in this BIG (6 billion people big) world? In the movie, Summer has grown up with divorced parents from a young age and doesn't believe in "love" or "marriage". However, the boy is a hopeless romantic who wants nothing more than to be in love with her. Summer says at the end of the movie, after getting married to another man, that she didn't believe in marriage until after she was in a deli reading her favorite novel and her now husband asked her about it. She said everything felt right, and then thanked the boy for telling her love was possible. She didn't realize it was until things fell into place with her new beau. She said she knew it was meant to be and "what if I hadn't gone to the deli that day? What if I had arrived 10 minutes late? What if I hadn't been reading that book? Everything lined up perfectly." She realized those things didn't line up with them and she just didn't feel that spark. And in time, he too realizes he was so blind with the good to see the bad that out weighted their relationship. I also think a lot of time what you think is "love" can be blinded with other temporary feelings of happiness, but that's another story. It makes me think about this a great deal. I myself am currently involved with someone I met under circumstances that seem too good & right too be true, but it makes me wonder - what if there's someone you're equally or more compatible with that lives half a world away? Or, your timing is just off - if being involved with someone else overlaps that time you could've met someone else. Are you only meant to be with just one person, or what if there's multiple people you could have equally as happy lives with? How do you choose? Are you meant to be with one person and the cosmos line up for you on that one special day you meet? Does a higher power control these things? Destiny? Fate? For now, I like to believe that everything happens for a reason, and I think that's what this movie tried to convey. On the 500th day of Summer, he met the person he was going to be with, but he wouldn't have been in that position if it weren't for her. Just something to think about....