Forever discontent, forsaken, and forlorn is the branch that seeks to grow its own fruit, and to glorify itself therein.
Spiritually speaking, all relationships serve one purpose: higher self-knowledge. This level of self-knowledge serves one purpose: awakening to the truth of one's self. Awakening to the truth of oneself serves one purpose: dying to oneself. Dying to oneself serves one purpose: rebirth. And rebirth is... the purpose and fulfillment of all relationships.