The Lover (1992)

In 1929 Indochina, a French colonial family and their 15-year-old daughter live in relative poverty. The girl, who is pretty depressed by her life and her family, goes to school in Saigon and is headed back one day when she meets a sexy older Chinese aristocrat (Tony Ka Fai Leung). He is instantly smitten with her, though he has absolutely no idea who she is, and offers her a car ride back to Saigon so she doesn't have to take public transportations like the peasants (or something like that). The next day, he waits for her outside school and takes her to a seedy hotel where he normally brings his mistresses and they start a rampant sexathon that turns into a full-fledged affair. They know neither of their families can find out, but they do anyway, and both of them give them a hard "nope." Ultimately, the Chinese dude has to marry his arranged wife, but not before we see each and every side of him, including a full frontal sex scene and a shower scene that shows off his ass. This, my friends, is what we call an affair to remember.