Soulmate

Soulmate (or soul mate) is a term sometimes used to designate someone with whom one has a feeling of deep and natural affinity, friendship, love, intimacy, sexuality, spirituality and/or compatibility. A related concept is that of the twin flame or twin soul – which is thought to be the ultimate soulmate, the one and only other half of one's soul, for which all souls are driven to find and join. However, not everyone who uses these terms intends them to carry such mystical connotations.
One theory of soulmates, presented by Aristophanes in Plato's Symposium, is that that humans originally were combined of four arms, four legs, and a single head made of two faces, but Zeus feared their power and split them all in half, condemning them to spending their lives searching for the other half to complete them.
Some followers of the New Age religion believe that souls are literally made and/or fated to be the mates of each other, or to play certain other important roles in each other's lives.
According to theories popularized by Theosophy and in a modified form by Edgar Cayce, God created androgynous souls, equally male and female. The souls split into separate genders later, perhaps because they incurred karma while playing around on the earth, or "separation from God". Over countless reincarnations, each half seeks the other. When all karmic debt is purged, the two will fuse back together and return to the ultimate.