Lake Bell's new film showcases little of the potential she flashed with her 2013 directorial debut, "In a World..."

It’s amazing how quickly potential can fizzle.

Four years ago, actress Lake Bell earned raves for her directorial debut, “In a World…” Had Bell segued seamlessly to a behind-the-camera career? Was she the industry’s newest double threat? “In a World…” didn’t deserve all that hype. It still showcased a fertile voice lurking within the actress.

Her sophomore effort is every bit as clunky as what you’d expect from a wannabe auteur. “I Do … Until I Don’t” is a cutesy title for an indie film apeing a mainstream rom-com’s worst tics.

Writer/director Bell plays Alice, a married woman struggling to have a child with her husband, Noah (Ed Helms). They’re facing financial problems on top of their fertility issues.

The marriage is swiftly heading south.

So is the bond between Cybil (Mary Steenburgen) and Harvey (Paul Reiser), an older couple who bicker when they’re not giving each other the stink eye.

They’re recruited to star in a documentary by a sleazy Brit (Dolly Wells) who thinks a seven-year commitment is best. So she stacks the deck, in true partisan style, to underline her points.

Paging Michael Moore!

Will the couples under her microscope fulfill her warped vision? Or can love blossom anew under some nasty circumstances?

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The men in Bell’s film behave in stereotypical fashion. Then again, everyone on screen does, too. Even conservatives will cry foul over the cliched hippies at the heart of the film. Amber Heard and Wyatt Cenac play a couple with an open relationship, but they only have eyes for every Flower Power bromide Bell can summon.

“I Do … Until I Don’t” packs a surprisingly retro appeal all the same. Marriage matters, gargantuan warts and all. The film’s villain isn’t monogamy but Wells’ one-note filmmaker.

It’s a reminder how … conservative rom-coms can be from an industry that prides itself on its progressive roots. Still, you have to bring more to the table than an “I Heart Monogamy” sticker.

Even conservatives will cry foul over the cliched hippies at the heart of the filmClick To Tweet

Twin attempts at shock value – a lame massage parlor sequence and an unflushed toilet – reek of comedic desperation, not insight.

Bell assembles a top notch cast here, but they can’t rescue this hackneyed assembly of relationship trauma. A few funny lines emerge, like Cenac admitting he’s a trust fund kid at heart. The rest of the banter is straight from a sitcom given the green light to work blue.

Marriage remains both complex, and essential, to the human condition. et’s cheer “I Do … Until I Don’t” for recognizing just that. And what a shame it reduces the institution to stale, sitcom-sized stories.

HiT or Miss: A sublime cast can’t save Lake Bell’s “I Do … Until I Don’t” from its limp rom-com tropes.