Feature film by David O. Russell, released in 1996. His other two films, Spanking the Monkey and Three Kings, dealt with incest and grand theft respectively. The protagonist in this film is likewise driven by a desire to indulge in something our society frowns upon, in this case adultery. It's all the more sinful since he still dearly loves his pregnant wife.
This was Ben Stiller's first lead role in a movie, and he carries the whole enterprise with his now famous blend of charming guilt and nervous wit. The story unfolds on the road as Stiller, his wife (played by Patricia Arquette) and an adoption agency employee attempt to track down Stiller's biological parents. As with all road movies, this is really just a device to dump the characters in a lot of weird situations across America, since you know they can't reach their goal until the third act.
Stiller's adoptive parents are hilariously played by Mary Tyler Moore and George Segal (now a regular on Just Shoot Me). They're annoying enough to make you believe Stiller would need to find other parents ASAP. His hippie biological parents are Lily Tomlin and Alan Alda, who at first seem a lot saner, but really theirs is just a different brand of neurosis. Initially the mother casting was to be swapped: Moore would be true mom, carrying her sitcom baggage as an air of familiarity. Russell later admitted this was a poor superficial idea and conceded to Moore's request to play the brasher role.
The cinematography of this movie is quite different from Russell's previous Spanking the Monkey: The constant handheld camera gives it a documentary feel, lending a nervous energy to the scenes. At its heart, this is a comedy, and so everything pretty much ends up okay after all the extramarital hijinks (even Arquette gets her axilla licked at one point). But I enjoy Russell's bravery to want to explore the twisted urges we all secretly share.