Christie Brinkley's messy divorce from her husband got under way Wednesday in full public view with her husband?s alleged mistress testifying.

The divorce trial between Brinkley and her fourth husband, Hamptons architect Peter Cook, opened in Suffolk County. Brinkley and her lawyers pushed to have cameras in the court and have the proceeding open to the public.

Cook set off a frenzy in the tabloids after he cheated on Brinkley with 18-year-old Diana Bianchi, who worked at his office. Brinkley filed for divorce from Cook in 2006 after revelations surfaced that he had an affair with the young woman.

Brinkley?s lawyers opened the trial with allegations that Cook spent more than $3,000 a month on Internet pornography. Cook's lawyer, Norman Sheresky, says of the porn: "It was wrong and he said it was wrong."

Sheresky also told the judge, "For goodness sake, she's on her fourth husband. Your honor, we're here because of the self-indulgent wrath of a woman scorned."

Bianchi testified about details of her sexual relationship with Cook. Cook also took the stand and testified he and Brinkley watched porn together. He also characterized Brinkley as an unfit mother who spent little time with her children.

Among the main points of contention for the couple is custody of their 13-year-old son and 10-year-old daughter.