In an atmosphere so crowded and lacking in privacy, sexual affairs would seem impossible. But “In the Mood for Love” exists in a universe where they are common, but still require a level of discretion.

Mrs. Chan works as much for her boss’s affairs as she does for her travel agency. She puts her husband to work to procure handbags, one for the boss’s wife, another for his mistress. She makes reservations for their dinner dates.

But he also does favors for people in the tight knit housing community — including buying a rice cooker for Mr. and Mrs. Chow during a business trip to Japan. Except when Mr. Chow goes to pay for the rice cooker, he is informed that she has already paid for it.

Books are borrowed — and expectations are set for when future books could be shared. Mrs. Chan and Mr. Chow share a love for kung fu stories. When she tries to drop them off one night, she finds out that Mr. Chow is not around and the couple has been quarreling.

We never see them quarrel, but we hear over and over about Mrs. Chow working late. The subtext is obvious. Meanwhile, Mr. Chow has a colleague who we find out later not only cheats regularly, he also visits brothels. He just happens to be the least attractive, poorest dressed man in the film.

When this colleague tries to rope Mr. Chow into a scheme so he can meet with Mrs. Chan, Mr. Chow tells him he wants nothing to do with his foolish plots.

All throughout, we never see Mr. Chan or Mrs. Chow. But every encounter between their spouses are warm and honest. Neither of them is the plotting type. And neither seems to be coveting the other either. It’s a respectful meeting of equals.

All of this is laid out in roughly five minutes of screen time, an incredible piece of subtle, economical film making. The atmosphere of Hong Kong in 1962 is not much different than the New York evoked in the 1960 film “The Apartment.” We also see some of this same vibe recreated in the early season of the AMC TV Show “Mad Men.”

The years right before the “sexual revolution” began were also highly sexualized, except in a way that was clearly skewed for the benefit of men. Because the Hong Kong economy basically demanded the employment of men and women, it’s in some ways a test case of the culture of spread worldwide over the next two decades. But it’s also influenced by Chinese culture, which tugs it back towards conservatism.

As we head into the second musical interlude of the film. Mr. Chan and Mrs. Chow are growing increasingly distant from their partners, and the melancholy is beginning to take over.