Two years ago, when Brinkley discovered that her husband of 10 years, architect Peter Cook, was having an affair with his assistant Diana Bianchi—that started when she was 18—"lucky" would have been the last word to come to Brinkley's mind. "It has been very painful for her," says a Brinkley source. "She really trusted Peter and loved him and he betrayed her. I wish this would all be over for her."
Instead, it is just getting started: On July 2 Brinkley, 54, and Cook, 49, are set to duke it out in a Long Island divorce court in what already promises to be a messy, mud-slinging trial. At stake? While the couple signed a prenuptial agreement before their 1996 wedding, the pair will go head-to-head on issues such as the custody of their kids Sailor, 10, and son Jack, 13 (from Brinkley's third marriage to Ricky Taubman; Cook adopted Jack shortly after he and Brinkley wed), and the distribution of their assets, which include several real estate properties and three boats.
For Brinkley, however, what's really on the line is her pride. "She feels empowered and encouraged," Alexa Ray, whose father is rocker Billy Joel, tells PEOPLE. "She's standing up for herself. I think that is admirable."
Allegations of other qualities have surfaced about both parties since Brinkley filed for divorce in September 2006. Cook's camp is accusing Brinkley of being a lousy parent (Cook once quipped about helping with their kids' homework: "Does [Christie] do it or does the nanny?"). Brinkley plans to counter with claims that Cook was a fan of surfing Internet porn sites. Her lawyer, Robert Stephan Cohen, has also subpoenaed Cook's former mistress Bianchi, whom Cook paid $300,000 as part of a confidentiality agreement, to take the stand on Brinkley's behalf. "She wants to stick it to [Peter], and she can," says a Brinkley pal.
Brinkley's fans, who have sent her dozens of e-mails encouraging her to stay strong, have played a huge part in the mother of three's new resolve. "I know there are many, many women going through what I am," says Brinkley. (Cook declined to be interviewed for this story via his attorney.) And with Suffolk County Supreme Court Judge Mark D. Cohen's June 20 ruling against a motion that would have closed the courtroom during the trial—something Brinkley had opposed (New York State trials are typically open to the public)—she is pleased that "the unfiltered truth" will be revealed, her attorney says. Counters Cook's lawyer, Norman Sheresky: "It's a disgrace. No parent in the world who cares for her children wants an ugly divorce case to be aired in public."
Might there be a chance of a settlement? Says Brinkley's lawyer: "We're not bluffing; we're going to trial. That doesn't mean we wouldn't be thrilled for a settlement, but it hasn't happened and doesn't appear to be happening." Cook's attorney counters: "[Brinkley] seems more than interested to go to trial. She wants a public flogging of this man."
In the meantime Brinkley is keeping a low profile at her $30 million Bridgehampton, N.Y., estate, taking Jack surfing or hosting playdates for Sailor. "She is so hands-on with her children," says longtime pal and Today correspondent Jill Rappaport. "Skiing to snowboarding to wind surfing, she's right there with them." Big sister Alexa Ray, who has spent much of the last year promoting her debut album, is keeping a close eye on her siblings as well. "They're all right," she says. "I can't say I don't worry about them. It's an intense situation. They've been feeling a lot of support at my mom's."
They also spend time with Dad every other weekend at his two-story home in the Hamptons, where he continues to run his architecture firm. "He's holding up okay," says a friend of Cook's. "He can take the heat." Same goes for Brinkley. "She was absolutely devastated by what Peter did," says a longtime member of Brinkley's circle. "But she is getting through it. She's really strong, and she has come so far."