Plot
Seth, a wealthy sitcom writer-producer with an Elvis fixation, meets Chelsea, an interior decorator, at his best friend Larry's wedding. He's sexually attracted to her while she's equally attracted to his wealth, charisma, and single-ness. They both ditch their wedding dates and start their own date that same night.
Advised by the bride Holly how she entrapped Larry into marriage, Chelsea tells Seth she has one rule: she won't have sex with a man until they have shared at least three meals. Seth proceeds to speed date through the evening so they actually do eat three meals. Serving Seth an ultimatum, Chelsea offers to sleep with him, but first demands complete exclusivity. Seth panics, but they are then seen having wild sex in the showroom of Chelsea's job.
Although they are a couple, Seth is pathologically terrified of marriage. Chelsea, in the other hand, is obsessed with getting married, while also short-tempered and manipulative.
She tells him she loves him after only four weeks. When Seth doesn't immediately reciprocate, Chelsea explodes and nearly ends things. Panicking again, Seth says he loves her. She then uses her beloved cat Gracie's disappearance as an excuse to move in with Seth, but Gracie reappears a few days later.
On a Valentine's Day getaway, Seth gives Chelsea jewelry when she expects a proposal. He insists it's far too early to consider getting married. An infuriated Chelsea disagrees, so Seth promises to propose in one year if things feel right.
Over the next year, Seth and Chelsea fight constantly, then reconcile with wild make-up sex. On Valentine's Day, Chelsea is expecting a proposal and is apoplectic when Seth gives her diamond earrings instead. As they've had a rocky year, he explains, proposing still doesn't feel right. Chelsea rants, raves, curses, ends their relationship, and throws the earrings into the Pacific Ocean.
Seth feels relieved until Chelsea files a palimony lawsuit and vows to take both his house and half of what he owns. Seth's lawyer warns him that breaking up with his girlfriend could cost him hundreds of thousands of dollars.
Forcing him to share the house, Chelsea tortures Seth, who is allergic, by filling it with rescue cats and replaces his shampoo with hair removal cream. Seth retaliates by binge-eating beans and farting excessively. He then kidnaps Gracie, whom he uses to trick Chelsea into jumping over the edge of the Santa Monica Pier and into filthy ocean water.
They briefly come to an agreement, sealed with angry hate sex. However, her lawyer convinces Chelsea to renege and files a restraining order to force Seth to move out of the house.
Pushed to his breaking point, Seth kidnaps Chelsea and takes her to a planetarium. She assumes he's going to murder her, but instead he proposes. Chelsea refuses until he shows her the ring she had previously demanded and Chelsea radiantly accepts. He has the ring appraised, sells his house so they can start anew, and convinces Chelsea to marry him on the Las Vegas strip, because no one in their families will attend after everything that's happened. He promises they'll renew their vows later with a big ceremony. In the airplane bathroom, Larry pleads with Seth to call it off, but the wedding goes forward anyway before an Elvis impersonator.
During their vows, however, Seth says, "I don't think so", and gleefully reveals that their engagement is a ploy. Chelsea dropped her lawsuit and moved out of his house, so she can no longer claim in court to live there. Seth further reveals that his dentist and his assistant posed as a married couple and purchased the house, which they will sell back to him, and that he bribed a jeweler to "appraise" Chelsea's glass engagement ring as a real diamond worth $50,000. A livid Chelsea grabs the chapel security guard's gun and shoots Seth, who is dancing triumphantly down the aisle, in the buttocks.
The Las Vegas Police Department arrests Chelsea and an ambulance takes Seth away as they scream and trade insults. Chelsea vows to sue him for breach of promise. Seth screams that Chelsea has "turned me off of women" and vows from now on to be "full-on Liberace gay". A sickened Larry and Holy conclude, “We need new friends.” As the ambulance drives away, a horrified Seth recants his coming out after being groped by a male paramedic. A newly single Chelsea tries in the squad car to propose marriage to the arresting officers, one of whom replies, "Lady, don't make me gag you."
