Now for the problems (and again - accompanied by very big plot spoilers; you've been warned). Nic and Jules react very differently to Paul. Nic remains distanced and cautious, unsure about what level of influence she wants Paul to have on her children's lives. Jules, who has recently decided to start a landscaping business, hits it off very well with Paul. He responds in kind, displaying an interest in her that Nic hasn't had in years. Paul just so happens to need some landscaping done, so he offers the job to Jules. Shortly thereafter, Jules and Paul engage in a passionate affair.
No longer about the kids and their new relationship with their biological father, the movie turns into another story of infidelity. This could have been interesting if only the writers had explored why this lifelong lesbian throws herself so fully at a man. Jules and Nic have a few issues to work through as a couple, but there is no indication that their union is about to crumble. Yet Jules goes off the deep end, displaying a voracious appetite for aggressive heterosexual sex. Paul, in perhaps the film's most fully realized character arc, discovers he has grown tired of endless flings. He genuinely wants to play a role in his children's lives. And he's also head over heels in love with Jules.
Forget about the lesbian aspect of the story momentarily. Nic is clearly the "man" of the house in a traditional sense, so imagine that this is a heterosexual couple who adopted a pair of siblings. The children seek out their biological parents. Their adoptive mother has an affair with her kids' biological father, unknown to her devoted, loving husband. I wonder what the reaction would have been to the same story, only without the same-sex element. Would anyone not sympathize entirely with the jilted husband? He's been depicted as an upstanding guy; an all-around intelligent, sensitive, and caring person.
I left The Kids Are All Right with the strong feeling that Cholodenko and Blumberg did not have a clear conception of the story they were trying to tell. It was too ambitious to tackle two big issues - not only the children with their biological father, but also the cheating spouse. Each of those issues deserved their own movie, or perhaps far more deft handling by the writers. Instead they've been crammed together, the first half of the story short-changed by the second and vice-versa.