There will never be proof, but yes i think it is a real concept. I think our souls exist in every microtubule of every cell in our bodies. Maybe we are some kind of spiritual souls having a human experience, and only the extremely blessed gets to find their soul mate.
To contemplate this one must believe marriage to be a spiritual relationship (for it to be "real"). I believe our hearts are created to love one, at a time. Therefore we mate. (Procreate with that one) As for pairing with someone on a "soul" level, our souls were not created for this purpose (to pair, to mate, etc). So after contemplating I'd have to say no, there's no such thing.