Sherri Papini's husband has filed for divorce just two days after she pleaded guilty to faking her own abduction six years ago.

Sherri Papini, 39, pleaded guilty on Monday to one count each of mail fraud and lying o a federal officer.

Her husband Keith Papini, who stood by her for six years while police suspected her alleged kidnapping had been a hoax, filed divorce papers on Wednesday, two days after her guilty plea.

"I am deeply ashamed of myself for my behaviour and so sorry for the pain I've caused my family, my friends, all the good people who needlessly suffered because of my story and those who worked so hard to try to help me," Sherri's statement to the court on Monday read.

A tearful Papini also said she would "work the rest of [her] life to make amends" for what she had done.

Sherri Papini of Redding leaves the federal courthouse after her arraignment in Sacramento, California, April 13, 2022. Photo / AP

The Northern California woman's plea puts an end to a six-year saga during which she has maintained the story that she had been kidnapped by two Hispanic women.

Papini was actually staying with her ex-boyfriend, nearly 966km away in Southern California's Orange County. Three weeks later, he dropped her off along Interstate 5 nearly 240km from her home.

She agreed to plead guilty in a deal with prosecutors reached last week and is scheduled to be sentenced on July 11.

Prosecutors agreed to recommend a sentence on the low end of the sentencing range, estimated to be between eight and 14 months in custody, down from the maximum 25 years for the two charges.

She also agreed to pay restitution topping US$300,000 ($446,000). That includes the cost of the search for her that covered several Western states, and the subsequent investigation into the "two Hispanic women" she said had kidnapped her at gunpoint.

Sherri Papini's husband Keith has filed for divorce days after she admitted to faking her own kidnapping. Photo / Facebook

When Papini was found, three weeks after going missing, she had bindings on her body and self-inflicted injuries including a swollen nose and blurred "brand" on her right shoulder. She had other bruises and rashes on many parts of her body, ligature marks on her wrists and ankles, and burns on her left forearm.

The married mother of two kept lying about it as recently as August 2020, she admitted in her guilty plea.

Papini has offered no explanation for why she did it.

Sherri Papini was missing for 22 days in November 2016. Photo / Please Find Sherri Papini/Facebook

Her attorney, William Portanova, said last week that he doubts even she knows and suggested "a very complicated mental health situation". He said her long-delayed acceptance of responsibility and punishment is part of the healing process.

Papini on Monday said she has been receiving psychiatric care for anxiety, depression and post-traumatic stress disorder ever since her return — more than US$30,000 worth of treatment for which she billed a state victim compensation fund and which is now part of her restitution.

"It is a mistake to assume mental illness is the cause of unusual behaviour," said Dr Ian Lamoureux, a forensic psychiatrist and frequent expert witness who teaches at the University of Arizona College of Medicine and the Mayo Clinic.

There could be a rational, if mysterious, explanation, Lamoureux said, though he cautioned that he has not examined Papini and many factors in the case remain unknown to the public.

Prosecutors say her faked kidnapping wasn't impulsive, and that she planned it for more than a year without her husband knowing. The former boyfriend told investigators they didn't have sex while she stayed with him.

- Additional reporting by AP