I agree, this diversion is not related to the topic at hand and should instead be discussed elsewhere. But just to clarify, what you are talking about is religious law or at most a social construct. It has nothing to do with "law of nature". What you are doing is confusing religious dictation or a social construct with "law of nature".

A Law of Nature remains permanent, regardless of the society or the evolution of human thought. Such as the law of gravity of the law of natural selection. Marriage is a social construct, it has nothing to do with laws of nature. The Wikipedia link that you posted pretty much clarifies it, but may you did not read it.