All souls originate from the Monads which is a 10th dimensional unit of energy that gives birth to individual souls similar to a solar flare separating into smaller branches. Most Monads separate into several souls, the Original Soul Families or Monadic Soulmates that are all united by the same original vibration. These souls incarnate together as families. best friends and romantic partners. If a Monad divides only into two souls we then have what is called a Monadic Twin Flame. These soul-types are usually polarized by the yin-yang Divine Feminine and Masculine. They can have shared past lives together or only meet in the spiritual reality. The pull between these souls is incredibly strong and it is not really beneficial for them to reincarnate together as a deep fixation can develop without learning the lessons they agreed to. Because of this they rarely incarnate together, at least on Earth which is a school of duality and slow moving energy. These souls can have have multiple past lives together on higher dimensional planets but not on the Earth. Some say they only incarnate together on the last lifetime on the Earth. Either way they will eventually find one another either in this world or in our other dimensional realms and merge together in unity.