Pregnant Malena is furious when Mel refuses to become a partner at his law firm because of the mandatory 10-year contract. Mel almost goes back and signs the contract, but he finally persuades Malena to let him pursue his dream: to open his own law practice. She sets aside some office space for Mel at home. After Dean and Sheri videotape themselves making love, Dean believes that he is unattractive. Sheri misinterprets his resulting shyness and fears that he thinks she is slutty. Finally, Dean admits the truth, and Sheri reassures him. Bobbi and Reggie must learn new habits now that they live together in Reggie's apartment. Their first mission is to find a mattress that they both agree is comfortable.
Malena and Sheri are upset because Mel's visiting friends Brian and Samantha Hunt are wild: Brian encourages Mel and Dean to stay out late partying, and Samantha mocks the women's staid lifestyle. Malena and Sheri try to be like Samantha and let their husbands do whatever they want, but the wives fail to make their men jealous by acting outrageously themselves. Finally, Malena tells Mel about her concerns. Unfortunately, Brian and Samantha buy a house across the street and plan to stay. Meanwhile, Reggie finds out that Bobbi secretly didn't give up her apartment when she moved in with him. He wants a total commitment, but she worries that she will be stranded like she was when her marriage ended. Reggie painfully agrees to get rid of his address book of women he has dated if Bobbi terminates her lease.
Unable to convince anyone to speak to her second-grade class on Career Day, Bobbi must allow Reggie to brag to the kids about his restaurant. Reggie also reveals that he and Bobbi are living together without being married, causing many parents to become indignant. Bobbi eventually lies to the children, saying she got married to Reggie, which he objects to until he realizes they might get wedding gifts from the parents.
Meanwhile, Malena doubts her maternal skills when she fails to befriend 3-year-old Nicholas, the son of troublesome new neighbors Brian and Samantha. She finally succeeds by feigning disinterest, but Nicholas still calls her "the scary lady."
Feeling unfulfilled, Sheri enrolls in college. Neglected Dean expects her to quit, but she vows to find enough time for her studies and her husband.
When hypochondriac Mel feels very sick, Malena assumes that he only wants attention and is having sympathetic pain corresponding to her pregnancy discomfort. Despite his friends mocking him, Mel continues to suffer until he must rush to the hospital for a real case of appendicitis. Malena guiltily waits on Mel while he recovers. Meanwhile, Bobbi ignores her friends' advice to trust Reggie when she sees him talking to his sexy former girlfriend, April Jamison. Reggie rebuffs April, even after she disrobes in his office, but Bobbi misinterprets when she bursts in. Reggie convinces her that he was faithful.
Reggie tells Dean and Mel that he plans to propose to Bobbi after seeing her in an unflattering way that didn't repulse him. Meanwhile, Dean repaints the kitchen in a shade of pink and Sheri doesn't have the heart to tell him she hates it.
Malena feels left out after Sheri spends her free time with another friend, which leads to an embarrassing public outburst. Meanwhile, Mel abuses Dean's generosity at work.
Dean unwittingly annoys Sheri by not paying close enough attention to her. Meanwhile, the wedding march might not be played after all when an argument between Reggie and Bobbi jeopardizes their nuptials. The off-again, on-again couple's trip down the aisle is put on hold after they each heed contradictory advice on how to celebrate the festive occasion. Malena persuades Bobbi to change the venue from the hotel reception room they had already booked to another building's terrace overlooking the city. Mel tells Reggie to scrap their original plans for a cash bar. The final clash comes when the bride and groom have a contentious war of words over their wedding song.
Bachelor and bachelorette parties are planned for Reggie and Bobbi, and everyone agrees not to hire any strippers. But both celebrations feature scantily clad dancers, one of whom suffers an injury.
Mel is hot to sign L.A. Lakers basketball star Shaquille O'Neal as a new client, but is side-tracked by a supermodel who is working for much more than just legal representation. While Mel tries to keep the relationhip strictly business, Shamira, the supermodel, is not interested in hearing about Malena. Meanwhile, Bobbi pesters Sheri about her relationship with Dean.
As her due date nears, Malena grows increasingly frustrated by Mel's lack of help preparing for the new baby and she has to turn to Dean for help, while Mel tries to shield her from their money problems and spends all his time wooing a new client. Meanwhile, Sheri spends much of her free time with Bobbi, who finds their outings less than exciting.
Sheri wants Malena to hire her as a nanny, but the mother-to-be would prefer to employ a professional caretaker instead. However, she does allow Sheri to sit in during the interviews, until her friend chases away a qualified candidate. Meanwhile, Mel employs Bobbi as a silent counselor when he takes on a large law firm during a divorce proceeding, and Dean pays Reggie to prepare meals for him.
Sheri is invited to a night of salsa dancing with her friends, but she doesn't know that their husbands have asked Dean to join them. Meanwhile, Reggie throws out his back during his honeymoon trip to Hawaii.
The fourth season concludes as Dean takes Malena and Mel to the hospital when the mother-to-be goes into labor. Once there, Malena tells her husband to keep his video camera rolling, no matter what happens. Meanwhile, Sheri arrives at the hospital and aggravates Dean.