Hi Christopher, thanks for your responses.
The Bible is a very old text, relevant, but old. Pre-marital sex, as I said in my article, was not a thing until the War. From my reading of the Bible, I read about situations like prostitution, sex with people other than their spouses, sex with people after their spouses died, sex with same sex, etc. I haven't encountered the discussion of pre-marital sex, if it's in the Bible, please let me know.
Secondly, the world has changed indeed. Marriage and sex had the almost sole practical purpose of reproduction, and prevention of men committing adultery. At least for the former, this is unlikely to be the main reason for marriage anymore. I'd love to hear your thoughts.
As a young person, I'm trying to reference to the Bible when adapting to modern day living. So I can only make my own analysis and conclusions.