Sex-addict Ruffalo meets tiny-food-eating Paltrow.

Sex addiction is one of those things. Like restless leg syndrome—it might be real, but it just sounds a little bit suspicious, doesn't it? The new film Thanks for Sharing knows this, and it makes a point of explaining that sex addiction, like all addictions, is about control, and the thing that causes you to lose it. Early scenes feature men walking down the street, looking desperately uncomfortable while clocking every short skirt and low-cut T-shirt they see, every billboard model, every sexy bus ad. It's kind of a revelation, actually—we all know that just about every aspect of our culture is hypersexualized. How must that feel to a man who's powerless to resist it? One of the weird, impressive things about Thanks for Sharing is that it actually made me feel compassion for that guy, instead of wanting to hit him with my purse.

Thanks for Sharing is about a sex addict—Adam, played by the always-great Mark Ruffalo, has been "sober" for 5 years when the film begins, meaning he hasn't masturbated and has had no extra-relationship sex. He doesn't allow himself to watch TV or use the internet; on business trips, he asks room service to remove the flat-screen from his hotel room so he's not tempted into a porn binge.

Adam's sponsor in Sexaholics Anonymous, played by Tim Robbins, does double time in AA. A gruff man who has fully embraced the language and lifestyle of recovery, he's quick to drive across town to help a friend who's struggling, but he's at odds with his own ex-junkie son (plot point!). Rounding out the crew is Adam's sponsee, played by Josh Gad, a creepy dude who's in court-mandated treatment after groping a woman on the subway, and who finds redemption through a friendship with a sassy, ecstatic-dance-loving hairstylist, played with remarkable ease and naturalness by the singer Pink. (That sentence got weird.)

And then there's Adam's new girlfriend, Gwyneth Paltrow, whose character seems shaded with the knowledge that everyone kind of hates Gwyneth Paltrow, and that the only way we'll accept her as a romantic lead is if we can root for her to fail. So she's well-cast as a tightly wound type A who's training for a triathalon and only eats food in teeny, tiny portions.

Given that the very premise evokes a raised eyebrow, Thanks for Sharing handles its subject matter with humor and sensitivity—the film is at its best when tracking the effects of addiction on interpersonal relationships, and the complex and deep bonds that can develop between people in recovery programs. But it is one of those movies that makes you wish filmmakers didn't feel so married to the notion of a "story arc." As it builds to its (ugh, too literal) climax, it stops feeling like you're spying on a fascinating bunch of weirdos with really interesting and well-developed problems, and more like you're watching a reality TV show where the producers are suddenly showing their hand, forcing personality conflicts to the forefront. There's much to appreciate here—great, funny, lived-in performances; some genuine insights about sex, addiction, and relationships; seeing Gwyneth Paltrow taken down a peg—but it's too bad the script wanders into such formulaic territory. recommended