According to the Kabbalah, every human soul comes from Adam Kadmon, and every embodied human soul is within Adam Ha-Rishon. At this level male and female were joined together in one holy image.
When the Adam Ha-Rishon was separated into man and woman- Adam and Eve- the holy souls destined to become human beings were also divided into male and female. Thus a person has a soul mate, a perfect spiritual counterpart, that he or she is destined to meet and unite with at some point in the transmigration of the soul. For the soul-being of both partners must have a sufficient degree of evolution and have accomplished all necessary tikkune of the soul before they are ready to meet and restore their unity. Both must be incarnate at the same time in male and female form, both must attain and embody their supernal soul, and the conditions in their environment- place, time, and circumstance- must be just right. Only then do soul mates meet and unite with one another. The union of soul mates is integral to the fulfillment of the ultimate mission of the Neshamah in creation and that the soul's mission cannot be completed apart from one's soul mate. A true mystical union must bear fruit and the two who become one must fulfill and complete one another.
Soul mates are able to meet and unite only through divine providence. It is a powerful event and the blessing of their union extends light and life to others. Soul mates uplift humanity and the world.
Glossary:
Adam Kadmon- Primordial human being; the first universe, which is inseparable from Ain Sof Or (the Endless Light); the universe of the soul of Messiah.
Adam Ha-Rishon- First human being; supernal human being, male and female in one body; the ideal state of the human being; the androgynous one.
Mystical Union- Union of the worshipper and worshipped; conscious unification with the divine or a divine power; term for Gnostic wedding ceremonies.
Neshamah- Holy soul; supernal soul; heavenly soul; divine nature
Tikkune- Correction, repair, mending, or healing; restoration of the holy Serirot to the ideal or original state; spiritual work on the soul.
Reference~ Gnosis of the Cosmic Christ, by Tau Malachi