Can we have some benefit for being married and housing,
Example - the married couples can place items inside the home.
or when you get married you and your beloved get a marriage certificate along with a Ring of Mara, when you place the marriage certificate inside the house it increases your cap size of items by +50 and +1 more people can enter the house, with a limit determined by the size of the house.
if you wanted to take this a step farther you could even offer a "Shrine of Divorce" inside the crown store for 4000 crowns. Placing the Shrine of Divorce inside the home will allow you to divorce your spouse turning your rings of mara into rings of divorce adding +25% exp.
Or you could even give us a marriage skill line which would only progress if you were in the same party as your spouse, and the skill line would give you benefits for partying with your spouse as well as allow you to do things inside housing such as 10/10 skill line would unlock a spouse NPC that you could place inside your house, the spouse NPC could do something new like Guild banker , or Crafting writs, or something creative.