Asguard is your girlfriend a cave man? I know she looks like a cave man, and this could explain her non-sapien female sexual aggression. I would look into it, many cavemen, or "maggers", live amongst humans largely unnoticed.
Does she shave a lot?
Women do enjoy sex, I think once they're doing it they actually enjoy it more than men, but they're instinctually inhibitted from fucking a lot because it is detrimental for the species. This is also why men, despite being open to fucking sluts, ultimately look down on them. There has to be this multi-pronged measure ingrained into the species to discourage women from wreckless fucking.
It's a test of a woman's character to refrain from getting too much dick, the more dick she can turn down the better she is at being a woman. Women are helped along with an instinctual reluctance to fuck. There's always a constant battle within women between this instinct and the base desire to feel sexual gratification. In lesser specimens of the female the former noble and important instinct is losing out to the latter shameful piggish lust.
Men don't have this inhibitor, because it in no way negatively affects them to impregnate many random women. It's up to women to be selective, and desirable in such a way that encourages men to stay with them for an extended period of time, willfully supporting and protecting the female long enough for her to successfully raise well adjusted offspring. The two are connected, probably the main consideration a man ponders when thinking about entering a serious long term committment (as opposed to a sexual encounter) with a woman is how good she is at turning down dick. It is at least comparable to the female's consideration of how good a man's potential is to provide for a family.
So it's really not about women not liking sex, it's about being instinctually sound and quality specimens of female homo-sapiens who, maybe on a sub-conscious level, understand that it is of great importantance to not fuck around.
People talk about contraception and fucking for fun and blah blah blah, but "condoms" aren't taken into consideration by the primal instincts of humans, so a woman who is comfortable, or even enjoys, fucking guys for fun, is still exhibitting the fact she is a poor quality human being.