Vintage supermodel Christie Brinkley and architect Peter Cook started yesterday the divorce fight in Long Island, N.Y. Brinkley’s estranged husband confessed he had sex with Diana Bianchi, his teenage lover, then paid her $300,000 hoping to keep their affair a secret.

He also dropped a rain of spending money on her, including $500 hidden under a rock. Earlier in the day, Brinkley’s attorney said Cook spent about $3,000 a month on pornographic Web sites. The architect also confessed behaving violently toward Brinkley’s daughter,13, with rocker Billy Joel.

“That is the man who’s come before this court and asked for custody of his 13-year-old son and 10-year-old daughter,” said lawyer Robert Stephan Cohen. Cook and Brinkley’s daughter, Sailor, had her 10^th anniversary yesterday.

“It was wrong and he said it was wrong,” Cook’s lawyer, Norman Sheresky, said of his client’s Internet porn fetish.

In opening declarations, Brinkley’s lawyer described the supermodel’s husband, 49, as an incurable adulterer, while his lawyer portrayed her as a woman so consumed with anger that she’s capable to turn children against their father.

The first witness in the case was Cook and testified on his relationship with his assistant Bianchi. He said that the affair lasted “less than a year”.

Brinkley was first made aware of her husband’s extra-marital affair from Bianchi’s stepfather just moments before she was due to speak at the Southampton High School graduation.

As the couple had a pre-nuptial agreement, the $30 million home and the amount of Brinkley’s assets are not up for discussion in this suit. The dissension is to primarily establish custody of their minor children.