So you'd date a woman who "rarely worked" because she might secretly be independently wealthy?
You can only go by what you see, not material things but work ethic, if she didn't know his financial situation..and why would she? What else was she to go by? It's his money and he seemed happy to keep it rather than spending it.
She was probably right about his motivations, just wrong about his wealth. If a man dated a woman who didn't seem to have anything going on career-wise..didn't seem to work much, but he was a go-getter who would fault him for moving on despite loving her?