Just as individuals experience a painful struggle between opposites in their journey to individuation, so does every dynamic, growing relationship between two individuals contain a certain amount of stress and tension.  By its very nature, the essence of “two-ness” is conflict.  Whenever the perfect isolation and solitude of a single soul is disturbed or influenced by the presence of another, there is bound to be tension.  This is a given in every relationship.
While this might seem to be a negative thing, the tension between the opposites is actually our promise for the emergence of the “spiritual” Couple within.  We need to accept the inevitability, indeed the desirability of tension in relationships because without it, creative growth and change cannot occur.  The image of an ideal, stress-free partnership is an unrealistic fantasy;  we should be careful not to become too attached to it.
Given that every relationship has a certain amount of tension, it is only when tension becomes the dominant factor and when conflict does not result in new, creative solutions to our problems but perpetuates injustice and unforgiveness that it becomes detrimental.  The important thing to remember is this:  when we look in the mirror of our relationship and see cracks and flaws, we need not worry unduly, but should simply continue with our inner and outer work.  But if we see serious dysfunction—for example abuse, evil, the tolerance of evil, or self-destructive behavior— the course of the relationship needs to be changed, and undoubtedly will be. 
Whenever one partner recognizes the unhealthiness of the relationship and conducts the necessary inner work to develop her or his archetypal potential, the relationship will either become healthier (if both partners can tolerate the discomfort of change), or else it will end. Change in one partner always results in change in the other.  As Jung said, “The meeting of two personalities is like the contact of two chemical substances: if there is any reaction, both are transformed.” If the relationship continues to grow and change, a more mature partnership will eventually be born.  If it ends, the partner who is growing becomes capable of forming a new, healthier partnership with another person who will be healthier than the previous partner.
The soul in its infancy wants to believe that marriage—whether to a human being, God, or both—will solve all its problems;  hence, the “happily ever after” motif of fairy tales and certain religious sects and leaders.  Without such assurances, many, if not most of us, are simply too afraid of suffering to risk leaving the dark, comforting prisons of conformity and unconsciousness.  Perhaps it is better that youth cannot conceive the sacred mystery of marriage.  If it did, we would never enter into it and the family unit as we know it could perish in one generation! 
But the maturing soul intuits that marriage—by which I mean any committed relationship between two individuals, whether sanctioned by society or not—is an initiation into an entirely new set of problems.  In every truly honest and intimate relationship there are times when we feel we are on the edge of a volcano that is ready to explode;  at other times the coldness in our breasts is glacial. 
Fire and ice;  this is the mystery and the miracle of the “marriage between the opposites,” a tension-filled dance which, if consciously borne and faithfully endured, can bring psycho-spiritual maturity.
You can order my new book, Healing the Sacred Divide, at www.larsonpublications.com