It’s been painful in recent years to see Todd Solondz, the once-inspired director of “Welcome to the Dollhouse” and “Happiness,” making his characters so lowly and pathetic they no longer seem real. If Solondz had kept his empathy for life’s everyday losers but put aside his compulsion to punish them for it, he might have made a comedy of barbed humanity like Azazel Jacobs’ “The Lovers.”

It stars Debra Winger and Tracy Letts as Mary and Michael, a couple in their late 50s who have entered the dead-zone phase of marriage. Their passion has left the building, but more than that, they’ve stopped pretending they have anything to say to each other. Their relationship is a glumly polite series of going-through-the-motions rituals (even when they sit in front of the TV having a glass of red wine, they’re drinking alone…together), yet the movie observes their anomie with a detached understanding that’s more graceful than masochistic. Winger has never toned herself down the way she does here, yet her radiance shines through; it’s become the expression of an ordinary woman’s fuddy-duddy desperation, and maybe her last true lunge at life. And Tracy Letts, who’s like Martin Mull’s geek brother, plays Michael with the punctilious, nearly percussive delivery of an over-controlled aging preppie nerd lost in his broken dreams.

A great many independent films have cued us to view a squirmy situation like this one through a lens that’s essentially comic. Jacobs, the director of “Momma’s Man” (2008) and “Terri” (2011), works in that tradition — he’s light and funny about marital despair — but he’s also a deadpan humanist who refuses to look down on the awkwardness he shows you. It turns out that Mary and Michael aren’t saps. Both are carrying on serious adulterous affairs, so while their passion may no longer be connecting them, it’s there for us to see. “The Lovers” is a comedy of Middle American doldrums that leaves you rooting for its characters instead of smirking at them.

Mary is sleeping with a somewhat younger dreamboat (Aidan Gillen), but the way “The Lovers” is structured, it’s Michael’s affair that lures the audience into the movie. His lover is a lonely ballet teacher, Lucy (Melora Walters), who’s in a rage over his delayed promise to leave his wife, though you get the feeling she’d be in a rage over something regardless of the situation. There’s a hair-trigger, borderline-personality-disorder aspect to the way Walters plays her — Michael isn’t just carrying on with Lucy, he’s trying to keep a lid on her instability — and this creates a fascinating dilemma. Michael’s choice seems to be between a stultifying comfort and an amorous tornado that he can scarcely handle.

You may wish that there was a more spontaneous momentum to Jacobs’ staging. He works in a deliberate, plotted-out way that mirrors the tics of middle-class unhappiness — the tasteful clean surfaces that keep everything under wraps, and all that — but he’d do well to let his scenes ramble and digress more. That said, he’s got a wild card at work in “The Lovers.” One morning Michael and Mary wake up, staring, excited and aghast, into each other’s eyes. Their relationship is over, yet they have never wanted each other more. And so they give in to that desire. All of a sudden, they’re the lovers, sneaking behind the backs of their clandestine mates.

Have they fallen back in love? “The Lovers” presents the situation as a rekindling of honest feeling that may also be a rite of passage in the grand arc of separation. These two need to remember who they were, who they are, to leave each other behind. The film’s chief catalyst is their son, Joel (Tyler Ross), who arrives from college with his girlfriend (Jessica Sula), full of anger about what he sees as the hypocritical disaster of his parents’ marriage. He’s right, but he’s also wrong. The film becomes a truth game about the past, though frankly it’s better when it’s less heavy.

Jacobs, for the first time, has a major distributor in A24 (who also financed the film), and it’s clear that they think there’s commercial potential in a marital comedy about people cheating on the people they’re cheating with, featuring the novelty of Debra Winger as a drone pining for liberation. They should probably tone down their expectations. “The Lovers” is quirky and touching, and it’s a good vehicle for two highly compelling actors, but the movie doesn’t fully break loose the way that you want it to. Yet Azazel Jacobs is onto something. He’s a filmmaker with a gift for showing people at their most nakedly desperate and spiritually disheveled and getting you to see yourself in them.