Price of a Married Woman: Perfume of Desires(2001)

A lonely guy is stealing garbage and then reading people's sex lives by sniffing and analyzing the waste. When his new neighbors introduce themselves to him, he becomes obsessed with the pretty wife next door. The poor girl is unhappy in her marriage and her husband can't get it up for her. When the neighbor stumbles home blind drunk one night, he reveals to that he's a chemist working on an aphrodisiac and gives our hero a sample to try.