The actress and the rock star got engaged in the Las Vegas desert in April 2002, but never set a wedding date.
Anderson wasn't wearing her engagement ring last week during a promotional appearance for People for the Ethical Treatment of Animals in Florida.
"The word that best describes me now is 'free,"' the 35-year-old told People magazine for its June 30 issue. "That's all I will say. I'm a mom, and that's where my life is at."
She also showed up at a June 10 party at the Playboy mansion without Rock, whose real name is Bob Ritchie. When Us Weekly magazine asked about future nuptials, she said: "Assume what you want about a wedding. ... I'm here with family and friends. That might be a hint."
Calls placed to representatives for Anderson and Rock weren't immediately returned Wednesday.
The two began dating in April 2001, when they met backstage at VH1's diva salute to Aretha Franklin at Radio City Music Hall in New York City.
In February, Anderson told TV Guide: "My priorities are my boys. I'm trying to create a new family with Bob and his son."
The "V.I.P." star has two sons — Brandon, 7, and Dylan, 5 — with her ex-husband, former Motley Crue drummer Tommy Lee. The two divorced after a rocky marriage and recently settled a tense, prolonged custody dispute. Rock, 32, has a 10-year-old, Bob Jr.