Hmm, sounds like a behaviourist's idea of clasical conditioning.
Or conditioning of some sort. So like Pavlov's dogs and the bell, then thier food, then they would salavate. Do this enough, and the dogs salavate do to the expectation of food when the bell rings. The dogs would hvae to of remembered that when the bell rings, they would get food or some deeper inner biological reasoning for this event...
So she smelled his "sent", and her body reacted to it. It remembered, possibly within her subconcious, that he used to wear that specific perfume, so she reacted as if he was still right beside her or near her. She has a learned response of feeling nauseated when she smells that sent, because it's directly linked to her ex. There are many ways to approach this, like getting her used to smelling the perfume till the learned response becomes, I'm not 100% on this but, an extinct response. (I might talk about her fear, or anxiety from when he abused her while they were together, would be coming out in a new way. Stress has to go some where, so if it gets deep enough it could become manifested physically. They dont' call it a pain in the neck for nothin eh!

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i'm sure there is more, and I do have my Psych text book here, but i'm a tad tired to look at it, sorry.
I don't really know much about the pakistani social structure, nor thier day to day society. You are on your own there dude. I'm sure some one will have more on it...
Not sure what you are looking for, but that's the best i can give you, let me know how i did... I love psychology.
Got a lot to say about it, especailly mental illnesses, and Brain plasticity.