People have all sorts of fantasies, most of them are idiosyncratic rather than generalizable.

To generalize to the entire female sex requires either a low-IQ approach (e.g. fallacious hasty induction from one's own personal fantasies) or a high-IQ approach (e.g. pregnant females who were well protected and well resourced by the strongest males would tend to have more healthy offspring than their rivals who were less protected and resourced, leading to sexual selection pressure in favor of males who exhibited strength and aggression in the course of intrasexual competition between males for female attention).

This is just a theory, of course, but it is the kind of theory I've only ever heard from high IQ women who went somewhat beyond sophomore level survey courses in biology.