About a quarter of the way into Noah Pritzker’s “Ex-Husbands,” two brothers discuss the vagaries of life while sitting at an outdoor cafe. The older of the two asks: “You know that feeling when you’re watching an experimental movie and you’re like 30 minutes in and there’s still no plot and no suspense, no real mystery?” He takes a drag on a cigarette, drops an expletive, and concludes: “That’s where I am in my life.”

Mr. Pritzker’s picture is by no means experimental, but the plot does wander, its suspense is mild, and mystery is all but beside the point. “Ex-Husbands” is a circuitous venture, an affable throwback to the kind of thing Woody Allen made back in the day: a New York-centric meditation on the privileged classes and their travails. As the title suggests, the bonds and boundaries of marriage are tested by those in the orbit of our protagonists, the Pearce family.

Or, rather, the Pearce men. We’re introduced to a dentist, Peter Pearce (Griffin Dunne), and his father Simon (Richard Benjamin) as they huddle in to see a film at Lincoln Center’s Walter Reade Theater. “Can I ask you a question,” the father asks, “… and I’m really not looking for an opinion if it’s a judgmental one.” Whereupon a bomb is dropped: Simon is divorcing Peter’s mother. Soon thereafter the wives of both men join their husbands, bearing popcorn and in a clear state of distress.

Fast-forward six years and we see Peter in action, performing dentistry but not altogether giving the procedure the attention the patient deserves. Simon is now living in an assisted-living facility, having been diagnosed with Alzheimer’s. Peter’s attempts at goodwill — providing dad with a framed poster of his favorite film, Ernst Lubitsch’s “To Be Or Not To Be” — are barely acknowledged. Peter is  nonplussed: He’s preoccupied by the divorce proceedings instigated by his wife, Maria (Rosanna Arquette).

Frazzled by the state of things, Peter decides on a weekend getaway to the resort town of Tulum in Mexico. The timing couldn’t be worse — at least for his sons, Nick (James Norton) and Mickey (Miles Heizer). The latter has scheduled a bachelor party at Tulum for his older brother and a cadre of best buddies during that very weekend. The last thing the Pearce brothers need is for their 60-something father to be lurking somewhere in the near vicinity. 

Peter agrees to cancel his trip, until he discovers that the ticket is nonrefundable. Throwing caution to the wind (and much to the ire of Nick and Mickey), Peter goes ahead and boards the plane to Mexico, and can’t help but keep bumping into his sons. A gentlemen’s agreement is reached whereupon dad will keep his distance in order to let boys be boys. The trouble is that not all the boys are in the mood for celebrating. 

Unbeknownst to all, Nick and his girlfriend Thea (Rachel Zeiger-Haag) have called it quits and are canceling the nuptials. When the cat is ultimately let out of the bag, Peter is the only person who is truly surprised by the news. The bachelor party participants are all too aware of Nick’s fragile mental state and the stress it has put on the couple’s well-being. 

All of which makes “Ex-Husbands” sound more on point than it is. The majority of the time, our heroes are in-and-out of situations on a catch-as-catch-can basis. This is a picture that isn’t in much of a hurry to get anywhere: Its characters drift down byways and get stuck in dead ends, some of them more provocative than others. Once Mr. Pritzker and his editor Michael Taylor settle into a rhythm, we get in sync with the movie’s lulling sense of bemused disappointment. Like the Pearce men’s trip south of the border, it’s not a completely unpleasurable experience.

The cast is exemplary, though one wishes Ms. Arquette was given more screen time. Eisa Davis is appealing as Eileen Link, a wedding officiator with whom Peter has a convivial flirtation. Messrs. Norton and Heizer plumb the intricacies of brotherhood with convincing nuance, and Mr. Pritzker’s script is peppered with inspired moments of mordant comedy. The bit about Simon’s hand? Gross — and priceless.

But, listen, it’s Mr. Dunne as the disheveled, disabused, and eminently placable Peter Pearce who elevates the picture’s sitcom-like trappings to something more poignant and recognizably true to life. We start to miss Peter once the ending credits begin to roll. Movie stars like Mr. Dunne, we need more of.