Gosford District Court judge David Wilson on Wednesday said the notes found in the husband's iPhone detailed about 300 debauched stories
The stories revealed the NSW Central Coast couple's predisposition to having sex with young children and the lengths they would go to satisfy their sexual needs.
Judge Wilson said police feared the stories showed the couple would have continued abusing children had they not been arrested.
The boy told police he was given drugs before being sexually abused (Dave Hunt/AAP PHOTOS)
The judge said the wife wrote about having sex with her brother from the age of nine and "she wished she found some older pedophiles to have their way with her".
"(The wife) goes on to explain how she worked at a nursing home where she allegedly had numerous sexual encounters with the male residents," Judge Wilson said.
"Another story has (the wife) working in a morgue where she interferes with two corpses and again goes into specific details about the sexual encounters.
"She stated the corpses are of a 10-year-old boy and a middle-aged female."
The judge said the couple, who cannot be named, had one fantasy of taking in homeless or deserted children and abusing them and also discussed kidnapping children to satisfy their sexual urges.
The couple filmed themselves abusing the vulnerable young boy over a five-year period.
The husband tattooed the image of a demon on the victim as a reminder of the abuse.
"The predatory behaviour changed what should have been a house of security to the victim into a house of horror," Judge Wilson said.
The couple pleaded guilty to 46 charges, including aggravated sexual intercourse with a cognitively impaired child and filming the boy for child abuse material between 2016 and 2021, when he was aged between 12 and 17.
The wife, 50, also admitted possessing prohibited weapons including a zombie sword, Taser and flick knife.
The couple was arrested in February 2021 after police raided their home searching for drugs and weapons and found a mobile phone with images of the boy being sexually abused. They also found 61 videos of the abuse.
Gosford District Court judge David Wilson is sentencing the couple. (Bianca De Marchi/AAP PHOTOS)
Judge Wilson said text messages between the couple discussing what they had been doing to the boy revealed their extreme depravity.
He said several texts showed they were aware of the victim's cognitive impairment.
In one text exchange, the husband, 51, told his wife: "He's an ugly little cry baby retard you flirted so much with."
The wife replied: "I still love our threesomes we had (with the victim) but it's time now for younger blood. Yes, I do want to fall pregnant to that ugly little retard so we can molest the child."
After the couple's arrest, the victim said he would be invited to their home on false pretences but every time "it was to f*** his wife, but I didn't want to, but I had to".
"I used to get free pot, free ice, free MDMA off him (the husband) to do that, to f***, to root his wife," he told police.
Judge Wilson will continue summing up the case on Thursday before sentencing the couple.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
Kids Helpline 1800 55 1800 (for people aged 5 to 25)