The basic assumption of Imago (Latin word for Image pronounced Im-ah-go) is that committed partnerships have a higher calling/mission than simply the pursuit of happiness.
The purpose is to help each other heal the childhood ‘wounds' that have resulted from imperfect parenting. Often people incorrectly assume that it is only in homes of abuse and profound neglect that “wounding occurs”. However as Freud said, "children are creatures that are never satiated, (therefore) there is no parent in the world who can react perfectly to the changing needs of the children".
The premise of Imago is that we are called into relationship in order to heal these relational wounds. Because we are born in relationship, and we are wounded in relationship (by imperfect parents), healing needs to occur within a relationship.
Imago proposes that we each carry an internalised blueprint of love which is made up of a combination of the positive and negative characteristics of significant childhood figures, our experiences of them and their attitudes toward us. This image is called the 'Imago”. Our selection of a partner is thus influenced by what feels familiar or previously known. In our quest for wholeness, the unconscious seeks a partner that matches this blueprint (best and worst of mom, dad and others). However this person initially is incapable of giving us the love we need as they carry the limitations of our parents.
Harville Hendrix thus contends that not only are the frustrations we experience as adults actually tied to unfulfilled needs or hurts in our childhood, but that choosing our partner is a consequence of our unconscious desire to heal or repair those wounds, so that now as adults we can get the love we need for wholeness and fulfillment.