I found it odd the song fades right after the lyric, “everyone you know someday will die,” yet we soon learn it’s rather fitting; despite a title that screams “erotic thriller,” the film actually is about a mother grieving over the loss of her child.

Making a miserable situation worse is that the woman, Emilia (Natalie Portman), is stepmother to the odd, awkward William (Charlie Tahan, “I Am Legend”), with whom she has yet to connect in any maternal, much less meaningful, fashion. William’s father (Scott Cohen, “Love and Other Drugs”) left William’s mother (Lisa Kudrow, “Easy A”) for Emilia, who worked in his law office. Their attraction may have worked on paper, but in the casting, I just didn’t see it; after all, Portman looks like Portman, and Cohen, a beefy guy who could be assembling sandwiches at a corner deli.

Still, I found the exploration of being a “fake mom” after a mere three-day stint as a “real” one interesting — at least for a while. Then the film decides to ditch its edge to become manipulative and melodramatic, turning into a message movie about SIDS, complete with an organized memory-walk event through the park that feels not at all like fiction, yet comes off awfully contrived at the same time. This happens so sudden, it’s like cinematic whiplash.

From there, “The Other Woman” lost me, especially with Emilia growing in abrasiveness to those around her — the audience included — and a handful of woe-is-me situations straight from the daytime soaps. Writer/director Roos has shown some real teeth before in screenplays (namely, “The Opposite of Sex” and “Happy Endings”), making the generic nature of this effort somewhat of a surprise.

Plus, the usually terrific Kudrow, whom Roos often employs in projects, is either miscast as a pediatrician or playing someone inhuman. And her third-act shot at redemption is all the more groan-worthy when you throw convenience aside and just think about the medical privacy laws that have been shattered. Roos is smarter than that.

So’s Portman. Here’s hoping her post-“Black Swan” Oscar clout to be more choosy.  —Rod Lott

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