This Paper is Concerned With the Disturbed Marriage. It is Proposed That Such Marriages Contain an Implicit Contractual Arrangement in Which Each Partner Tries to Use the other to Get Something that he Feels is Lacking in Himself. The Pseudosymbiotic, Parasitic Nature of this Relationship, Which is Here Called "Instrumentality," is Explored. Instrumentality is Seen as Pervasive in Most Areas of Human Involvement, but as Finding in Marriage a Uniquely Convenient Vehicle. Given this Kind of Relationship, a Number of Repetitive Interactions May be Expected to Follow. Some of These Events, and Their Destructive Spiraling, are Briefly Traced. Contrasts Between the so called Normal Marriage as a Model and the Instrumental Marriage are Suggested.