Christie Brinkley Describes "Nightmare"

Christie Brinkley says it was a "nightmare" to put on a brave face and throw a birthday party with 30 kids amid revelations that husband had an affair with a teenager.

But the model - testifying Monday at the custody portion of her Long Island divorce trial - says homespun family celebrations are part of a lifestyle that means the world to her.

She tearfully told the court: "That's the most important thing to have a big, happy family."

Brinkley says she tried to spare her kids the messy details of the breakup, including her discovery of husband Peter Cook's Internet porn habits.

She told the children: "I think Daddy has fallen out of love with me." But she assured them they would always be "very, very loved."

By Frank Eltman