I think your maybe losing your animal instincts, Maverick :)
Seriously, though, I really think that we have become so accustomed to sanitised scents, the smell of soaps, perfumes etc that our deep primitive urges diminish.
Every male and female produces natural sex scents. Some get embarrassed by it or think that it is abnormal and try to mask it with soap/perfume.
I agree with Scarlett, that the scent shouldn't be bad unless it is an infection, or unless you are not used to the natural scent of woman. We all produce our own distinctive scents. If it is an infection, your girlfriend should have it checked out.