'I Do' doesn't: Capable comic cast encumbered by clumsy cutting

“I Do ... Until I Don't” boasts a crackerjack cast of comic actors struggling to spin gold from the straw-dry dialogue of a lackadaisically edited, visually compromised, controversy-adverse, pro-matrimonial romantic comedy.

A shrill, corrupt documentary filmmaker, Vivian Prudeck (Dolly Wells), manipulates three (mostly) well-paid couples into proving her belief that the institution of marriage died a long time ago,

“Don't be daft!” Vivian thunders at a gathering of her female fans in Florida's Vero Beach. “Love is not sustainable! Nor is marriage!”

Vivian, famous for her popular film “Tween Jungle,” theorizes that society would be better off if couples contracted to stay married for seven years, with renewal options.

Because people live much longer now than the creators of marriage could imagine, the mate-for-life model has become a curse, she says.

Her hypothesis is actually intriguing in the same way that the human body was never designed to match our increasing life longevity.

But “I Do” displays little interest in using humor to seriously explore the long-term viability of wedded bliss.

The screenplay — written by director/actress Lake Bell — dismisses Vivian as a hypocritical, boo-hissable villain intent on destroying an institution she can't join.

Mary Steenburgen and Paul Reiser deliver the most nuanced performances as Cybil and Harvey, longtime married folks who sleep with an iceberg between them.

Harvey never passes on an opportunity to skewer his wife, even though his caustic insults (Cybil says she has a present for him, to which Harvey replies, “Anthrax?”) feel forced and not in character.

Bell plays Alice, who's been trying to have a baby with her relationship-inept hubby Noah (Ed Helms). She has reshaped her life and dreams to fit Noah's needs and wants, prompting her to crash Vivian's documentary.

To bring in extra money, the sheltered Alice takes a part-time job at the local “Your Welcome Spa” where she gives men happy-ending massages. Her first client? A middle-aged man named Harvey.

Alice's little sister Fanny (Amber Heard) and her hunky hubby Zander (Wyatt Cenac) make up the third couple chronicled in Vivian's doc.

Fanny and Zander (perhaps a reference to Ingmar Bergman's classic “Fanny and Alexander”?) seem perfectly happy with their open marriage and multiple sexual partners. Oh, oh! Zander begins to rethink the virtues of monogamy by the final act.

“I Do” gets done in mostly by the editing, a visual assemblage with all the snap and crackle of cold linguine.

Cinematographer Wyatt Garfield seems daunted by all that space on his extra-widescreen canvas. Sometimes, actors appear to be swimming at the center of what “The Neverending Story” would call “the nothing.”

“I Do” achieves a pinnacle of cloying contrivance when a pregnant woman (Hannah Friedman) insists on giving birth at home, compelling the main characters to participate in an agonizingly protracted event that begins to look like a torture sequence from “Game of Thrones.”

Maybe Vivian's next doc will target motherhood.

“I Do ... Until I Don't”

★ ½

<b>Starring:</b> Lake Bell, Ed Helms, Mary Steenburgen, Paul Reiser, Amber Heard, Dolly Wells

<b>Directed by:</b> Lake Bell

<b>Other:</b> A Film Arcade release. At the River East 21 and Century Centre in Chicago, plus Evanston's CineArts 6, Highland Park's Renaissance Place, Glenview's Glen Stadium 10 and the Lake in Oak Park. Rated R for language and sexual situations. 103 minutes