I'd say Rebecca came from an upper middle class family. She probably chose to marry a ,man chosen by her parents are suitable. Perhaps he was extremely wealthy, which may explain why she interacts with upper class society the way that she does. She was probably always trying to be like them for her husband. So she can sort of put on a facade. This husband was probably sort of distant from her, maybe even having an affair with someone else. She probably never really felt close to him and he was not supportive of any of her interests. So when he rejected her idea to open a shipping company this resulted in a huge fight that lasted hours. It resulted in her leaving him. She didn't tell her parents she had left him and headed straight for Cape Suzette to start her dream and to become independently wealthy. So she's technically not divorced, and her husband has yet to tell anyone yet either. For now they both pretend the that the other does not exist.

I'd say the enterprising divorcie with a little girl from down the road, left with little from her jerk of a husband and made it big in her own business when all around said she'd fail.