Your case is not unique, and is part of what has to be dealt with. I have dealt with many men who have had casual sex with girls who are not virgins, this is the state of the world today.
It is the state of the world as it has always been. To be fair, it happens in much greater numbers now than in ancient times. People don't get stoned to death as often as they once did for this sort of thing and, more importantly, we have birth control, so casual sex is a lot more common today than it once was, but it isn't a new thing.
The problem with your theology, whether applied in Biblical times or today, is that you would assert that God demands people live in misery. Let's take my situation.
Once, some decades ago, I had sex with a virgin young woman named Laura. That means we were married in the eyes of the Lord, according to your teachings. Ok. All well and good so far. Then, I abandoned her. I ran off to another state, and not too long after to another woman. This makes me an adulterer and one upon whom God might pour out his wrath. Ok. Fine. I hope you are wrong, but I won't say there's anything inherently ridiculous about that belief.
But what of Laura? Having been abandoned, the only way that she can live a life free of sin is, apparently, to live a life free of sex. She must spend her days unloved and childless, all because at age 18 some cad took her maidenhead and kissed her goodbye? Now she must live alone, or hunt me down and kill me, or spend eternity in a lake of fire. Do you really think God wants that, or that the Bible demands it?
The commandments and passages you have cited from the Bible demand that a man not do what I did. If there is divine retribution in store, I have clearly earned it. But Laura? To punish her for my actions would be cruel, and I have never heard a believer insist that God is cruel.
And in my particular case I was up front about my intentions, and she went to bed with me anyway, so maybe she was a little slut who deserves her lake of fire. On the other hand, she would have continued the relationship, even at a long distance, if I had been willing, so that ought to count for something. Regardless, for every Laura in the world, there are plenty of others to whom men pledged undying love in order to get them into bed, and either changed their mind later, or possibly never intended to keep that promise in the first place. Shall those women who suffered so much at the hands of the cads they fell in love with suffer even more at the hands of God?
No one who gives it a moments thought would agree, and nowhere can you find a passage in the Bible that demands it.