Diane Ackerman, a naturalist/journalist, wrote in her book A Natural History of the senses that a component of violet scent will temporarily "numb" the human sense of smell after inhaling the perfume, but that after a few minutes our nose will pick it up again.

The idea that a human nose "can't handle them all at once" is perhaps true for certain individuals but certainly does not apply to all humans. Since, for instance, there are individuals with incredibly acute senses of smell,like those hired by perfumeries to test fragrances. They are able to discern an incredibly wide range of aromas few of us are sensitive too.

Google aroma/olfactory/sense of smell, etc and you will find a list of articles on the subject, including several that discuss the issue that individuals experience the same aromas differently--physiologically, not just "emotionally". Ackerman's book was very popular when it was published and is very likely in your public library. She is very thorough in that discussion. Also, there was an interesting book published recently called The Emperor of Scent that discusses the phenomonen (but is much drier in its presentation of the science).

My partner cannot smell violets at all. I can, and love the scented varieties.

The human body can smell something, but the odor fades way, the longer you smell it. I would think this is a survival mechanism.