i came across a reference to this in one of the course books for my Couples & Family Therapy course, and since i had to look it up, i figured i'd share :)
summary comes from
http://marriage.about.com/od/marriagetoolbox/a/tasksofmarriage.htm, and all the references are to Wallerstein's book, The Good Marriage1. (i have it on reasonable authority from the coursebook in my hands that the principles are equally applicable to all intimate relationships, regardless of gender/orientation/marital status, etc.). a decent quick online summary of the points is available here:
http://www.planetpsych.com/zPsychology_101/relationships/making_marriage_work.htm.
Nine Tasks of Marriage
Task 1. Separate yourselves emotionally from your family of origin. Doing so helps you to "invest fully" in your own marriage and redefines the "lines of connection" with both of your families.
Task 2. Build togetherness with one another but create autonomy for one another at the same time. Everyone needs time and space to recharge. Your coupleness and individuality are both "central throughout the marriage."
Task 3. Protect both your privacy and time alone when you become parents. This will help you "absorb the impact" that having a baby can have on your marriage.
Task 4. Learn how to cope with crises. It is important that the two of you maintain "the strength of the bond in the face of adversity."
Task 5. Express your differences, anger, and conflict in healthy ways. You can do this by fighting fair and creating a "safe haven."
Task 6. Make your sexual relationship a high priority. "Protect it from the incursions of the workplace and family obligations."
Task 7. Laugh with one another. You can "keep things in perspective" with humor and you can "avoid boredom by sharing fun, interests, and friends."
Task 8. Encourage and support each other. It is important that the two of you "provide nurturance and comfort to each other."
Task 9. Don't forget your early romantic years. Keep those years alive "while facing the sober realities of the changes wrought by time."
1 - The Good Marriage. How And Why Love Lasts.: By Judith S. Wallerstein and Sandra Blakeslee. Boston/New York: Houghton Mifflin Company, 1995. 352 pp.