If god meant marriage as one man, one woman, I'd be interested in what logical gymnastics are used...?

Question

... to explain 2 Samuel 12:8

Here, YHWH tells David that had he only asked, YHWH would have provided David with even more wives.

"And I gave thee thy master's house, and thy master's wives into thy bosom, and gave thee the house of Israel and of Judah; and if that had been too little, I would moreover have given unto thee such and such things."

Answer 1

I'd also be interested in the logical gymnastics you would use to explain the point of your question.

So, if I understand you correctly, are you asking why David had more than one wife? Such a question would only make sense if you started with the assumption that the Bible forbade more than one wife.
The truth be told, the Bible does NOT forbid more than one wife. Nowhere does it mention this. In addition, David was not the only biblical figure to have more than one wife.

In Judaism, being married to more than one wife is forbidden due to rabbinical edit given in the 9th-10th century.

Answer 2

As if that was the only thing David ever did to piss off God...