A man and woman pass the Test of Marriage together. Both must have received the test of marriage from the Uharmony. You have to have passed the Initiation of Harmony and be level 7.
At a ritual altar:
Once married, each partner may access any buildings or property of his or her spouse.
In addition, each partner may log on as his or her spouse merely by selecting an option from the Utilities menu. (billing functions and password changing are disabled when you use a spouse login, so credit cards and passwords are safe)
There is divorce, but we don't know details of it as of yet.