Then the gov shouldn't intervene in the question of marriage, and people should be able to enter into any marital arrangement they want?? So what is it, free for all in terms of marriage, or some kind of governmental regulation of marriage?
The state has a fundamental interest in regulating marriage, so why shouldn't it get involved?
This whole notion that the gov should just stay out of things; the result would be economic, social, etc. arrangements being determined by the economically and socially powerful, as it has always been historically with, I think, questionable results by 21st century standards.
Are you capable of nuanced thinking? Really, it's not always black and white.