In “The Freshly Cut Grass,” there’s a scene that captures how people who’ve been married for a while, and are in the thick of raising children, can snipe at each other in dog-whistle ways that mean nothing and everything. Pablo (Joaquín Furriel), a professor at an agronomy college (he basically instructs his students about dirt), says that he thinks his teaching job is “shitty.” But his wife, Carla (Romina Peluffo), has no job at all (and is up for an interview), so she takes his comment as an insult. She snaps at him, then apologizes and lays her head on his shoulder; we think their snit is over. But Pablo doesn’t move a muscle, which leads her to say, “Does it bother you if I touch you?” No, he says, “how could it bother me?” Well, she explains, she wanted a hug. But there’s a power duel in play, expressed in the job talk and the hug talk. With a worldly flourish, the movie says: This passive-aggressive punching is what too much marital war now looks like.

Celina Murga, the Argentian director and co-writer of “The Freshly Cut Grass,” was born in 1973, and she works with a lived-in understanding of the jadedness that can set in when couples have fallen into the routines of family life to the point that the grind of it blots out everything else (like love and affection). The movie jumps back and forth between two couples. In addition to Pablo and Carla, there’s Natalia, played by Marina de Tavira (the Mexican actress who came to a new prominence with her performance in “Roma”), and Hernán (Alfonso Tort). Natalia also teaches at the college, and her marriage has reached a comparable semi-dead end. The film follows her as she slips into an affair with one of her graduate students, even as Pablo does the same thing with one of his.  

Remember when adultery equaled drama? It wasn’t so long ago. The sex, the secrecy, the moral duplicity of it all has been powering movies since movies began. And part of the luscious universality of adultery is that it cuts across class differences the same way it cuts across levels of movie art, from the vulgar to the highbrow. It’s the engine of soap opera but also at the center of brainy meditations by Rohmer and Bergman.

The French, of course, have long been famous for viewing adultery with a shrug, as if it were an inevitable aspect of bourgeois life, so why not just embrace it? But “The Freshly Cut Grass,” in its earnest Argentine way (the film is actually a co-production of Argentina, Uruguay, Germany, Mexico, and the U.S., and it’s being presented by Martin Scorsese), hits a level of contempo casualness about adultery that trumps even the what-goes-around-sleeps-around flippancy of French art cinema in the ’70s. There is not the faintest shadow of moralistic judgment here. The attitude of the filmmaker seems to be: Our lives, in the current climate, are so anxious and cantankerous and messy, so mired in the latest iteration of the gender wars, that if a little unfaithful action is necessary to stir things up, who could really argue?  

I’m not saying that “The Freshly Cut Grass” is advocating adultery. But what it shows us is a pair of straying professors who act without knowing what they’re doing, because the midlife family blues has driven them to their wits’ end. And the decision to act, to upset the apple cart of their lives, turns out to be necessary. So, the movie says, why judge?

The actors are all urgent, doleful, angry, hungry, convincing. Yet I wish the two stories weren’t designed in such parallel, rhyming ways. In each case, the family has two kids, and each of the professors is up for the same job promotion. They each hook up with a sexy, free-minded partner who’s of a generation that’s a lot more casual about doing the “wrong thing.” So there’s never any real suggestion of emotional convulsion.

Of course, they’re also sleeping with their students, which is a much bigger deal than it used to be. Both get caught in the exact same way (which, I have to say, hits a note of undue contrivance): They’re each photographed, in public, in a subtly compromising position, the photo then circulated on social media. Each one then has an identical meeting with the department chair (“I won’t do anything because no formal claim has been made. But things are being said…You’re a professor, it’s not a trifle”). And each returns to his or her home, maybe a little more willing to see the beauty of what they have.

There’s a dramatic downside to this worldly, almost neutral view of adultery. Whereas a movie like “The Lovers” — or “Unfaithful” — gives off a high-voltage charge of passion, “The Freshly Cut Grass” is relentlessly cool and circumspect. Yet there’s a value to its observational humanity. It wants us to register the differences between what men and women face in our society (though the stories are so alike the differences end up minimized). Mostly, though, it wants us to observe how families have become, in their outwardly conventional way, the most combustible units on earth.