I think this would be a great idea, at least for the actual marriage. Going along with the game mechanics, I like the description line, as it keeps opportunistic males off my girls when they say married, but it has some drawbacks too. Like massive OOC bleed with people assuming they can know something like that because it's written, when in reality they have no way of knowing it ICly.
I do not however like the idea of having to divorce that way. If two players decide they do not want to write together anymore, I don't think in a game setting, that they should have to go together to a registry to be freed of each other. I don't think they should even have to be standing next to each other to do it. I'm not sure if someone can type /divorce *name* or if you have to click the broken rings icon to do it, but I think sometimes, space is a good thing. After all, this is a game, and forcing that level of realism on what is potentially a painful experience is not fun. If I had had to RP out my last divorce in front of a registry, or other characters, I would not have continued playing the game. Simple as that.