In "Sex in Human Loving" (1973), Eric Berne makes this entertaining classification of how some marriages proceed, by analogy with upward scans of the letter shapes AHIOSVX and Y.
An A marriage starts off as a shotgun or makeshift one. The couple are far apart, but soon find a single common bond, perhaps the new baby. This is represented by the crossbar of the A. As time goes by, they get closer and closer until they finally come together, and then they have a going concern. This is represented by the apex of the A.
An H marriage starts off the same way, but the couple never gets any closer, and the marriage is held together by a single bond. Otherwise they each go where they were originally headed.
An I marriage starts off and ends with the couple forged into a single unit.
An O marriage goes round and round in a circle, never getting anywhere, and repeating the same patterns until it is terminated by death or separation.
An S marriage wanders around seeking happiness, and eventually ends up slightly above and to the right of where it started, but it never gets any farther than that, leaving both parties disappointed and bewildered, and good candidates for psychotherapy, since there is enough there so that they don't want a divorce.
A V marriage starts off with a close couple, but they immediately begin to diverge, perhaps after the honeymoon is over or even after the first night.
An X marriage starts off like a A. At one point there is a single period of bliss. They wait for it to happen again, but it never does, and soon they drift apart again, never to reunite.
A Y marriage starts off well, but difficulties multiply, and eventually each one finds his own separate interests and goes his own way.
There are undoubtedly many other types of marriages, but they do not fit into the alphabet we use, so they will have to be left for a more complicated system of classification.