“An Infinite Ache,” a world premiere at the Long Wharf Theatre by young playwright David Schulner, tells the story of a couple’s relationship, beginning with an awkward first date and ending in a muddle of Viagra and hearing aids.

Gawky dreamer Charles (Peter Smith) keeps telling himself to be mysterious and aloof. Failing to be either of those, he faces the terrifying ordeal of inviting high-strung, charismatic actress-type Hope (Angel Desai) into his apartment under ambiguous circumstances. But instead of being put down quickly and mercifully, the date, in part fueled by Charles’ imagination, turns into a love for not-quite-all-time, a love haunted by a mystical “infinite ache” (a phrase borrowed by Schulner from poet Pablo Neruda).

Before anyone has time to catch their breath, Hope and Charles are moving from the euphoria of daily morning sex to the addictive bickering of couplehood. It careens from diamond rings (the cheapest one at Tiffany’s) to strollers, with both struggling to catch up. In a particularly endearing scene, the couple reacts to the birth of their first child:

“I want to run up to people in the street who don’t have babies and yell ‘get one,'” proclaims an exultant Charles.

Meanwhile, Hope discovers her maternal instinct, in a big way: “I am capable of destruction,” she informs Charles.

Along the way, the ingenious set, designed by Marjorie Bradley Kellogg, slowly unfolds in stages, matching the couple’s upward mobility. The same room morphs from Charles’ barren studio to a plush suburban home as doors that used to lead to cramped closets open up without warning to shiny bathrooms, and an ugly hallway becomes a sconce-littered beauty. At one delightful moment, a Mary Poppins-ish scene change has topiaries glide out of a small suitcase.

Like its characters, and particularly Charles, the play itself is a bit gangly and awkward. Despite an intensive series of workshops at the Cape Cod Theatre Project last summer, the play still shows signs of the relative youth of its otherwise talented author. Its form, a modified stream-of-consciousness, focuses on the highpoints and lowpoints of birth, death, fights and sex, but leaves out significant portions of the story.

Under the direction of Greg Leamin, the acting artistic director of Long Wharf, Hope and Charles are endearing but not idealized. But at times, they and their relationship begins to seem a bit brittle. Who are these people in the between-times, one wonders. Fortunately, the dimly lit scene changes, representing the quiet progression of the characters’ lives, balance the constant banter and the bonanza of non sequiturs.

Of course, all good things must end, and the play, with its dual themes of time and love, cannot afford to forget this adage. Charles’ wistful plea, that “I just wanted to stand still a minute,” is in vain. The show falters most in the “home stretch.” Both Smith and Desai put in alternately tender and laugh out loud funny performances as the young couple. But as the characters age, and jokes about midlife crises and a multiplicity of therapists fade, both the actors and the author face a major challenge.

Smith, in particular, had his work cut out for him in making the difficult, but only partially believable transformation from gangly post-adolescent to creaky grandpa. Schulner faces another dilemma, his impending death. Eek! It’s the elephant in the room for a show about two individuals with the audacity to include the word “infinite” in its title. Schulner’s solution, to more or less ignore it and then retreat, is less than satisfying.

Nonetheless, its commentary, a little nutty, slightly profound, and replete with infectiously funny moments, makes “An Infinite Ache” both powerful and pleasant.