Young and sheltered?
From the hoi polloi, the working classes, the unwadhed masses most certainly, but court politics, no way.
She went to an exclusive finishing school. The girls of landed gentry are bred for this sort of thing.
The fairy tale Beauty and The Beast was written for them. Belle, a beautiful young girl is wedded to an older man by her father. At first he appears like a beast but she grows to love him.
The aristos have always been about political marriages.
And Princes if Wales have always had mistresses.
The Prince Regent's marriage to Caroline of Brunswick is a case in point.
But they all did it.
Now ghis msy seem like an alien world to you, and it is to me, but for the aristocracy it's perfectly normal.
She would have had some idea of what she was going into.