In a committed relationship or partnership, there is a relative overlap of one partner's personal boundary with that of another. The areas outside the overlap are essentially, the two partners' private selves, with their private thoughts, emotions, plans, decisions, actions outside the awareness of the other, and of course the place where one's personal life's goals ("mission in life" or "purpose in life") reside. The area inside the overlap is the intimate, shared space of the relationship, itself.
In Codependence, the overlap is LARGE, and approaches a length to width of the overlap, of 1.0. The two partners overtake the privacy of the other, and make most of the shared resources, dominate the attention and concern of both partners. This is a setup for someone to overly sacrifice their own personal life's goals, as well as surrendering their resources to endeavors that do not serve their private selves. The destiny of such a relationship is a struggle for control of what is mutual between them, until the bigger bully confiscates the majority of resources of time, energy, money and attention to goals that aren't really mutual and balanced. You might say that "too much" intimacy causes this effect. This relationship is ruled by "boundary holes" in both parties.
In being overly in Independence, the overlap of boundaries is more of a sliver, and is not very intimate or shared at all, "too little," the ratio of length to width, approaching infinity. The two partners lead relatively separate lives, and would make one wonder whether they are even in a relationship at all. They might as well be single. This relationship is ruled by "boundary walls."
However, in Interdependence, the overlap of boundaries is "just right" - the Goldilocks Zone. It is a ratio approaching what has been called the Fibonacci Number, the Divine Measure, which is the ratio of height to width of 1.618... The perfect number of proportion in the beauty of nature or art. Yes, even in a relationship, there can be mathematical models of perfection, where the amount of shared resources, joint goals, and invested time, energy, money, attention, personal, private life's goals, and everything else that is shared, are perfectly balanced against the natural shared needs of coupledom and partnership.
In fact, it might make good sense to you that the total area for each partner, "outside the relationship" is just a tad MORE in amount than the total amount shared BETWEEN them. That might run contrary to what you are used to, given that we are all bathing in media that suggests one "give their all" to the relationship, not to "take care of yourself, first." And yet, that is the healthiest stance to have in a relationship, where no matter what, you always have a "sense of self" that is bigger than the relationship. From that standpoint you have more to give the relationship from a strong foundation.
One can then bounce back and forth, easily, between being somewhat independent for a time, and being intimate at others. The "Goldilocks Zone" assures this, with its perfect ratio in which we know each other to the core self, and yet do not overtake their identity or resources for more than the relationship bears, nor find ourselves forced to sacrifice forever, our dearest personal goals.
