Maybe a HK version of "Fatal Attraction" (i haven't seen the Hollywood
movie so I'm not sure) where a married man has sex with a woman who
turns out to be a psychopatic stalker.

A married man, Yuen-chi Lam (Kevin Cheng) with a wife, Ching Lau
(Rebecca Zhu) and a kid, saves a young woman, Fong Yu (Dada Chan)
suffering from claustrophobia from being locked in a toilet booth.
When visiting a bar after work he sees her again, gets really drunk, and
follows her home, wakes up in her apartment the next day after having
sex with her.

Lam is a family doctor and is reasonably nice to Fong Yu, but she starts
to stalk him and the question over which Lam ponder is, could she be
dangerous to him or his family ? Does Panda bears crap in the woods ?

Film presented in widescreen 2.35:1 with mandarin or cantonese audio
DD 5.1 with english subtitles. Teaser, Trailer, Gallery and featurette