Taking the stand in a Long Island, N.Y., courtroom, Brinkley testified about "the day my world was completely shattered" – the day she learned that husband Cook was having an affair with a teenager.
On June 25, 2006, just after the supermodel delivered the commencement speech at Southampton High School, Diana Bianchi's police officer stepfather tapped her on the shoulder, Brinkley, 54, testified, and told her her husband wouldn't leave Bianchi, his then-assistant, alone. "I turned to look at Peter. His face was so tense ... he was saying, 'No,' " Brinkley told the court, reenacting how Cook, 49, was shaking his head.
"I thought 'Oh my god. It's true. He did it.' I knew from his face. It explained the feelings I'd been trying not to feel."
Her voice filled with emotion, Brinkley, dressed in a crisp blue shirt and a black skirt with a teal sweater draped around her shoulders, looked Cook in the eye as she testified. "I saw little Jack's face looking at his dad, the man and me," she said referring to her son, who was with them. "I thought, 'I am going to pass out.'"
She said that her vision started to blur and her knees started to buckle. She searched for a chair to sit down so she could collect herself.
Then, she said, she pretended to tie her shoe so no one would see her breaking down, and asked Cook to "get her out of here."
After the three arrived at her Bridgehampton home, Brinkley asked Cook for the car keys. "I drove away from my perfect life," she said, choking back tears. "I thought I had the picket fence. I thought we were happy."
Brinkley: I Felt ShatteredBrinkley also testified about Cook's use of Internet porn, saying his habit upset her so much because he appeared intent on personally meeting the women he found online.
"I found conversations of him trying to lure girls saying he would take them shopping, saying he would pay them if he could see their face," she said. When asked how she felt about discovering the porn she said, "I felt really stupid. Why didn't I know? Why wasn't I aware of this? I felt humiliated. I felt shattered. I just felt grief-stricken."
She said when she talked to him about the porn, "he said it was an abberation, something he only got into now because of the guys in the office."
As court broke for a lunch break, Cook lashed out at Brinkley, telling reporters: "Shrek was more believable than that." Brinkley will face cross-examination when the trial resumes. Earlier in the day, the model's best friend, Today correspondent Jill Rappaport, who first introduced Brinkley to Cook in 1996, detailed how devastated Brinkley was by the affair.
Hours after hearing the shocking news, Brinkley pulled over on a public road and "when I got there, Christie was lying on the ground huddled over with her hands on her knees. I thought she had died," Rappaport testified. "She was sobbing … almost catatonic. I grabbed her by the shoulders and she said, 'Can you believe this? Please tell me this is a nightmare.' "
Rappaport then accompanied Brinkley back to her home and comforted the sobbing supermodel in her bedroom. Later on that evening, according to Rappaport's testimony, Brinkley explained to her children – Sailor, 10 and Jack, 13 – why their father wasn't coming home, first telling Jack: "Daddy and I had a fight ... All mommys and daddys have fights and we're going to take a little time out."
The nasty divorce trial began on July 2, when an emotional Cook broke down on the witness stand as he admitted to spending $3,000 a month on Internet porn and detailed his trysts with Bianchi. Later on, Bianchi, now 21, and Brinkley’s daughter Alexa Ray (whose father is singer Billy Joel) also testified.
What's at stake for Brinkley and Cook? The contentious couple are battling over custody of their children Jack and Sailor, along with the distribution of assets which include several real estate properties and three boats.
Christie's Heartbreak: Read PEOPLE magazine's article about how Christie Brinkley was blindsided by her husband's shocking affair