Something seems a bit off in the story at least as far as the 19th century situation in the islands. My grandmother was English from Barbados. If the story had focused on social class and wealth, then it would have sounded more accurate.
Up until the 19th century and freeing of slaves, the whites and mixed-race children of plantation owners occupied what was the middle class of the island. After emancipation of the blacks, the middle class virtually collapsed with skilled ex-slaves competing for the few middle-class jobs, incomes collapsed.
And with that, the division on the island was not black and white, but rich and poor. And while the rich were virtually all white, the poor were black, white, and mixed race.
My great-grandfather told his daughters to leave the islands and go to America and never return in the 19th century. There was no future for any "free" person, white or black, where the vast majority of land was controlled by the very wealthy, who imported most of their goods leaving very few middle-class jobs focused on serving the poor.
Before the emancipation of blacks, many poor whites from Europe like my grandmother's ancestors had migrated to the Caribbean to fill the very limited number of tradesmen jobs on the island. My ancestors arrived in the 1600s. Life was hard and many women died giving birth, so much so, that the life expectancy for women was far lower than for men.
One of my ancestors got married when she was 14 years old, girls grew up fast at that time. For those with Carribean heritage, it is amazing how easy ancestral research is, since for the most part generations attended the same church and the records are still there.
With emancipation, the number of people all competing for the few "good" jobs drove down wages and so as the 19th century progressed, no one other than the very wealthy enjoyed "privilege". It is not surprising the attractive young women of any race would find a better life as the mistress of a wealthy plantation owner, who likely married not out of love but someone from his own class. And so, marriages were in many cases loveless "business" arrangements and men and women sought "love" elsewhere.
In some ways you were better off being a "mixed race" child of a wealthy plantation owners. Some of them cared about their lovers and the bastard offspring that came from those unions and made an effort to provide them an education and patronage to secure one of the few decent jobs.
Regarding your question about "could you do it"? Knowing the reality of life on the islands, I personally would not condemn any woman white or black, who decided that life as a wealthy man's mistress was preferable to abject poverty, but I admire my grandfather for using what little money he had to send all his daughters to America hoping they could find a life in America... they did.
