NY- Christie Brinkley’s estranged husband agreed to pay his former teenage lover $300,000 to keep quiet about their trysts, it has been confirmed by PEOPLE.

Architect Peter Cook, 49, now in the midst of a bitter divorce from the supermodel, gave Diana Bianchi the money to remain mum and not take him to court for sexual harassment.

Bianchi and the married Cook began their affair when she was just 18 and had begun working in his office.

“What Cook did is prey on an 18-year-old girl. It’s a textbook case of why an employer is not supposed to carry on a relationship with an employee,” Bianchi’s lawyer Joseph Tacopina has said.

Cook “first physically made advances at me … probably a month after I started working there,” Bianchi, now 21, told the New York Post.

Last March, Cook’s lawyers negotiated a secret deal in which he paid Bianchi $300,000 to keep the details of their relationship private – and out of a courtroom.

A source close to Cook told PEOPLE, “Peter settled because he wanted to his children left out of it. That’s the difference between them – he wants the children left out of it and [Brinkley] wants the kids in it.”

Obviously, it hasn’t worked out that way. The judge in the case has ruled that the Brinkley-Cook divorce be made public, and Brinkley’s lawyers have subpoenaed Bianchi as a witness, something even a confidentiality agreement can’t trump.

Peter Cook and Diana Bianchi

Photo by: Splash News Online
“She’s been subpoenaed to testify, and if called to testify, she will testify truthfully,” Bianchi’s lawyer told PEOPLE.

The settlement agreement between Cook and Bianchi had been reported in 2007, but its exact amount hadn’t been revealed until Tuesday.

Cook and Brinkley wed in 1996. They have a daughter Sailor, 10. Cook also legally adopted Jack, Brinkley’s 13-year-old son from a previous marriage.

Brinkley first learned of the yearlong affair between her husband and Bianchi when confronted about it in 2006 by Bianchi’s father, Southampton Village, N.Y., police officer Brian Platt.