IN THE MOOD: Pete (Paul Rudd, left) and his wife Debbie (Leslie Mann) are enjoying a rare romantic moment, which Pete will undoubtedly dispel later on with inappropriate behavior, such as flossing his teeth at a critical moment.

We first met Pete (Paul Rudd) and Debbie (Leslie Mann) in Knocked Up (2007), when the couple was in crisis, primarily because of her controlling behavior. She unreasonably suspected her husband of cheating on her because of the odd hours he kept as a rock and roll talent scout.

Their subplot was an amusing diversion from the main story about the farcical plight of a popular TV host. In This Is 40, Pete and Debbie, who we learn are in an unhappy marriage, have become the protagonists of a battle-of-the-sexes comedy.

At the point of departure, we find them both on the verge of turning 40-years-old. Debbie’s in denial, still trying to pass for 38, and is dreading the impending arrival of her birthday.

Meanwhile, Pete has regressed behaviorally, and routinely undermines any potential romantic mood by inappropriately flaunting unappetizing behavior such as flossing, among others, thereby ruining the mood. So, it comes as no surprise that the spark has gone completely out of their relationship.

This sad state of affairs is established during the picture’s opening tableaus when we see how, between their demands of work and raising two daughters (Maude and Iris Apatow), Pete and Debbie are too drained by the end of the day to even think about lovemaking. In fact, the most passion either exhibits is for their jobs.

He’s the CEO of a struggling retro record company that represents obscure has-beens like Gram Parker, and she owns a trendy boutique that is in financial trouble because of embezzlement on the part of a trusted employee. In addition to their marital problems, they may also lose their multimillion-dollar McMansion.

It’s important to note that This Is 40 was written and directed by Judd Apatow, who is the master of the shock and exploitation genre, whose productions have glorified profanity, potty humor, graphic sexuality, and nudity. This offering won’t disappoint his diehard fans in that regard, and even has the rudiments of a plot that may be of interest to people whose IQs are in the room temperature range.

Very Good (**½). Rated R for sexuality, nudity, crude humor, drug use, and profanity. Running time: 134 minutes. Distributor: Universal Pictures.