There are movies about the beginning of happy relationships and movies about their bitter or tragic disintegration. Very few, however, focus on the in-between time, where work, kids, and moments of mid-life desperation can make even the most committed relationships miserable.

That’s what makes “The Kids Are All Right” such a rare and special film. It doesn’t treat its characters like ethically-depraved monsters or moralistic fairy tale royalty. It’s funny, superbly acted and unexpectedly real in even its most sitcom-y plot twists.

Julianne Moore and Annette Bening star as Jules and Nic, a longtime couple raising two teenage kids (Josh Hutcherson and “Alice in Wonderland” star Mia Wasikowska). Both kids were conceived from the same sperm donor, and one day they decide to track down their birth father. He turns out to be Paul (Mark Ruffalo), a motorcycle-riding, organic restaurant-owning free spirit who has never committed to any long-term relationship.

Let’s put a stop to some assumptions right here. “The Kids Are All Right” is an R-rated film about a lesbian couple, but by no means is it an issue-driven film. There’s no talk of gay rights or marriage, and any person in a longtime relationship can probably find something relatable and true in its depiction, regardless of political leanings.

On the surface, Nic and Jules seem to have a comfortable and respectful relationship. Through the introduction of Paul into the family dynamic, their personality differences (and parenting styles) come to a head, as does their unresolved resentment toward each other’s career choices.

All the performances are spectacular, with Moore and Ruffalo providing their typical screen consistence. Bening proves to be the cast’s biggest standout, finding a believable balance between Nic’s tightly-wound, acidic exterior and her sensitive and sympathetic core. Moore gets to deliver the film’s climatic dialogue, but it’s Bening’s wordless reaction that sticks with you.

Co-written and directed by Lisa Cholodenko (“Laurel Canyon”), “The Kids Are All Right” is the rare summer indie that will no doubt be remembered come Oscar season.

Pity that you missed it in Coeur d’Alene. The film opened last Friday at the Regal Cinemas Riverstone 14, but, at press time, was not listed for showings this weekend. “The Kids Are All Right” is still playing at the AMC Cinemas at Riverfront Square in Spokane.

Grade: A