Originally titled "Love and Other Impossible Pursuits" (after the Ayelet Waldman novel on which it is based) and premiering at the 2009 Toronto International Film Festival, "The Other Woman" has since gone through a name change and is finally seeing a Video On Demand/limited theatrical release, one assumes, due to Natalie Portman's recent popularity resurgence for her Oscar-bound role in 2010's "Black Swan." If that is what it takes to get this wonderfully performed character drama—at once delicately handled and emotionally harrowing—out to audiences, then so be it. Written and directed by Don Roos (2005's "Happy Endings"), "The Other Woman," like "Black Swan," is first and foremost a blazing showcase for Portman's talent as she makes the final transformation from gifted child actor to fully adept adult thespian.

Emilia Greenleaf (Natalie Portman) is the young wife of successful attorney Jack (Scott Cohen), struggling to prove herself to 8-year-old stepson William (Charlie Tahan) and the doubting naysayers around her. Little by little, via flashback, the prickly circumstances that have led her to her present are filled in. Once an ambitious assistant at Jack's law firm, she quickly met and fell in love with her married boss. She never meant to be a homewrecker—Jack assured her his marriage to Carolyn (Lisa Kudrow) was on its last leg anyway—but that's what she became all the same. Just as Emilia and Jack embarked on their new life together, tragedy struck when their three-day-old daughter Isabel passed away from Sudden Infant Death Syndrome. Eight months later, Emilia is still floundering, faced with caring for a stepson she continues to make mistakes with and a bitter Carolyn whom she can't seem to please. If there is any hope in finding her place in a world far harsher than she ever expected it to be, she first must come to terms with the troubling events surrounding her newborn's death that she has kept locked within herself.

In lesser, more obvious hands, it is easy to imagine how "The Other Woman" could have become a drippy, manipulative Lifetime movie. Even if there are times when it does threaten to seem like such, writer-director Don Roos and his adroit cast never let it cross over. The subject matter is potentially melodramatic, to be sure, but its emotions are affectingly reeled in, its tone more earnestly melancholy than sensationalistic or premeditated. In Emilia is an engrossing lead protagonist, a young woman who means well and earns the viewer's sympathy, but is not above her own set of flaws and a touchy temperament. Some of her reactions in dealing with William are understandable; as a child, he's not always tactful, and Emilia, having faced the pain of losing a child without the experience of motherhood, isn't sure how to cope when he keeps going on and on about selling Isabel's crib and unused stroller on eBay. She knows her daughter is no longer with them, but giving away her things is tantamount to giving away the hopes she had for her future—something she can't yet reconcile. Likewise, when William repeats what his own mother said and tells Emilia that Jewish law states Isabel—only three days old when she died—was not yet a person, it's like a hard punch to the gut.

Overly sensitive but not intentionally cruel, William is in many ways a product of what Carolyn has hammered into him; he believes, probably mistakenly, that he's lactose intolerant, for example, and sees it as the end of the world when he is denied acceptance into Manhattan's top private schools. Emilia tries to disprove the former, only for it to blow up in her face, but does have words of wisdom to impart about William's education. Having gone to Harvard herself, she tells him it's not all it's cracked up to be. Besides, he's only eight; he has plenty of time before he has to start pressuring himself about his post-high school career. If Emilia is doing her best with William without getting anything in return—Carolyn viciously snaps at her at one point that being a stepmother is "less than nothing"—Jack sees in his wife a coldness in her eyes, a silent but not invisible nagging resentment that William, unlike her birth daughter, is destined for a full life. Indeed, Emilia likes William very much, but that doesn't make it fair that most people live to an old age while a select few don't even make it past their first week on the earth.

Natalie Portman receives ample support from her co-stars, but she is the one that must carry "The Other Woman" throughout. She is in every scene, and it is through her that the viewer is asked to exist in her shoes. Portman is exceptional, reverberating with guilt and heartache without ever drowning Emilia in a pool of woeful tedium. Beyond her troubles is a spark and the knowledge that she will, little by little, heal. As William, Charlie Tahan (2010's "Charlie St. Cloud") makes for a pleasing partner for Emilia, their troubled but hopeful relationship as stepson and makeshift mother the heart of the picture. A scene where they ice skate together in Central Park is lovely in its simplicity, writer-director Don Roos seeing it as a great opportunity to build their respective bond without turning it into an excuse to add further conflict.

As Carolyn, the matchless Lisa Kudrow (2010's "Easy A") digs into a key supporting role that the actress makes up in indelibility what she lacks in screen time. Snappy and short-tempered, Carolyn seethes with animosity—a personality that Kudrow nonetheless finds the humor, pathos and humanity in. When she finds herself, of all people, imparting words of solace to Emilia just when she needs it most, the results are revelatory—both for the story's ultimate catharsis and for Kudrow's remarkable handling of the material. Also memorable in small but complimentary turns: Debra Monk (2009's "The Great Buck Howard") and Michael Cristofer (director of 2001's "Original Sin," appearing in his first acting role in fifteen years) as Emilia's separated parents, and Lauren Ambrose (2009's "Where the Wild Things Are") and Anthony Rapp (2005's "Rent") as Emilia's closest confidantes Mindy and Simon.

"The Other Woman" traverses familiar terrain—think of it as a cross between 2010's "Rabbit Hole" and 1979's "Kramer vs. Kramer"—but doesn't come off as derivative. Hitting upon several domestic hot-button topics without turning into a soap opera or a message film, the movie strikes honest chords time and again. Writer-director Don Roos never loses sight of Emilia as the one worth following, carrying her and her fervid quandaries to a conclusion that feels natural and satisfying. Sometimes it's not about solving one's problems, but about making peace with what cannot be changed. That "The Other Woman" understands this, not only in regards to Emilia but also extending to the rest of the characters, is particularly revealing and unusually wise.