I realize that this is a fairly old post, but I'd like to put in my few cents worth.
I feel that soul mates very much do exist. However, I don't necessarily feel that a soul mate is someone you've known in any previous life, I don't necessarily feel or believe that it is someone that you will have a romantic involvement with. I do not believe that a soul mate has to be a member of the opposite gender. I believe that they can be of any status in our lives, of any age, of any gender, of any background. A soul mate will always challenge us to reach our potentials, not rub our failures in our faces, put a boot in our rears when we need it and don't realize, and they will, if need be, hurt us emotionally if that is what it takes to move us from one bad point in our lives into a better light. ... My opinion anyway
Cheers!