According to Greek Mythology, humans were originally created with 4 arms, 4 legs, and a head with 2 faces. Fearing their power, Zeus split them into two separate parts, condemning them to spend their lives in search of their other halves.
It is true that most people spend a great majority of their lives searching for that "special" someone. Some claim to have found their soul mate; someone who matches or compliments them perfectly in every characteristic and/or aspect of their life. Have these people really found their other half? Who knows... People change all the time. That's one reason why we have break-ups, separations, and divorces. The questions you need to ask yourself are these: Will you still love the person standing in front of you 10 or 20 years from now? Will one of you change into someone the other can no longer love? Or will you learn to love these changes and grow together with them? Whether or not you are willing to admit it, everyone changes. It may be a little change or a big change. But even the small things matter.
As cynical as this may sound, you will never know if the one you currently love is truly your other half. Sadly, people fall in and out of love all the time. Some do this more easily than they know or are even willing to admit.