Personally, I do not understand what business government has at all in my marriage, or anybody else’s.
As somebody who comes from one country (Germany), lives in another (USA), and got married in a third (St. Lucia, in the Caribbean), I’ve been exposed directly to the different rules everybody has around marriage, and it’s a bit ridiculous. According to whose am I supposed to do what with my wife? Do I really care? Just leave it up to the people who want to be married and perhaps their customs and traditions and religions; they will figure it out just fine.
P.S. And when you get into divorce, it gets even more ridicolous. E.g. what if you got married in a country that permits divorce, but live in another that doesn’t? And it goes downhill from there if you consider remarriage.