By Michelle Tan
July 21, 2008 12:00 PM

Just before 9 a.m. on July 7 Christie Brinkley pulled up in her white Prius to the Suffolk County Supreme Court building in Central Islip, N.Y., greeting the assembled media with her trademark high-wattage smile. “I hope everyone had a happy Fourth,” she said as she began her march toward the courthouse entrance in pink heels. “I am looking forward to my independence day.”

As Brinkley knows, no independence day is complete without fireworks, and since her messy and highly publicized divorce trial began on July 2, explosive details about Brinkley’s marriage to architect Peter Cook have surfaced. Though Cook’s affair with his then-18-year-old assistant Diana Bianchi led to the couple’s 2006 split, it was “just the tip of the dysfunctional iceberg,” claims Brinkley’s attorney Robert Stephan Cohen. Among the trial’s shocking revelations that have generated daily tabloid headlines: Cook, 49, once had a monthly $3,000 online porn habit, and his issues with Brinkley’s daughter (by singer Billy Joel) Alexa Ray allegedly drove Cook to dunk her head in a bucket of water. (Cook refuted this claim.) “I thought I had the picket fence,” a teary Brinkley, 54, said from the witness stand on July 3. “I thought we were happy.”

Instead, she now finds herself battling Cook over how to split up their family—and their assets: Although the pair has a prenup that protects most of Brinkley’s fortune (estimated to be at least $60 million), some $3 million worth of property acquired during their marriage is in dispute. “Did Christie think about giving him whatever he wants? No,” says Cohen. “If you throw money at him, he’ll come back whenever he wants more.”

An even bigger sticking point for the couple is who should have custody of their two children, Sailor, 10, and Jack, 13, whom Cook adopted at age 4. (Jack’s biological father is Brinkley’s third husband, Ricky Taubman.) On July 8, court-appointed psychiatrist Dr. Stephen Herman testified that the supermodel should be the primary parent, classifying Cook as a “narcissist.” “While most people need some ‘feeding’ of their egos, Mr. Cook has an insatiable appetite,” Dr. Herman wrote in his report. When asked about Cook’s current relationship with Suzanne Shaw, Dr. Herman said exposing his kids to a new girlfriend now is “bad judgment.”

Since Brinkley filed for divorce in 2006, she has maintained primary custody of Sailor and Jack; Cook sees the kids on Wednesdays and every other weekend. Now Brinkley wants them to sleep at her Bridgehampton, N.Y., home on Wednesday and Sunday nights, while Cook, like Brinkley, wants sole custody, which would make him the decision-maker about the kids’ health and education.

It would also entitle him to collect child support. Yet Cook’s lawyer Norman Sheresky insists money is not his client’s motivation. “Not only is he an able father, but he will do what she won’t, which is promote a good relationship with their mother,” says Sheresky, who fears Brinkley is brainwashing the kids against their dad. Sheresky also blasts Brinkley for not supporting a motion to close the trial to the public. (Divorce cases in New York are typically kept open unless a judge rules a public trial would cause demonstrable harm to a child.) “He’s a father who wants to protect his children,” Sheresky says. “You’d think she’d be a mother who’d want to.”

On July 7 Brinkley testified it’s not her character that should be questioned. While she has been able to “move on” from Cook’s indiscretion, Brinkley said she worries about leaving her kids with a man who would “chase a teenager.” Then, referring to one of the more tawdry allegations against Cook, she added, “Sneaking out of the house—leaving a wonderful life with his kids—to masturbate on the World Wide Web makes me wonder about his judgment.”

Brinkley also claimed that, at times, Cook’s method of disciplining the children was “too overwhelming with his use of force.” (Says Sheresky: “I think it’s outrageously untrue.”) And when it came to Cook’s behavior toward Alexa Ray—”He would constantly be picking on her,” Brinkley said—things got so bad that “one day I told Peter, ‘You married me and my two children. If you can’t love all of us, I can’t stay in this marriage,'” recalled Brinkley, who credited Cook for going to therapy to work through his issues. Nothing, however, compared to the “nightmare” of discovering in June 2006 that her husband had been cheating on her with Bianchi, whom Cook had hired in ’05. (Brinkley later said, “I forgive [Bianchi] completely.”) When Cook denied the affair, Brinkley demanded his computer passwords so she could check his e-mail. Then she discovered the depth of his betrayal: Under aliases such as “wannaseeall,” Cook subscribed to porn sites such as “I found conversations of him trying to lure girls … saying he would pay them if he could see their face,” said Brinkley. “I felt shattered.”

Now the model, who spent July 4 with Alexa Ray and her ex Billy Joel at a barbecue in Sag Harbor, N.Y., says she is struggling to rebuild her life. “I haven’t even thought about dating,” Brinkley testified, her voice cracking as she reviewed the way her life has turned out. “All I ever wanted,” she said, “is a happy family.”