A rapist demonstrated "an entitlement to the victim's body" because the pair were "in some kind of relationship", a court has heard.
"Never in my most abhorrent nightmares would I have imagined that this would be the end of our love story," the man's former partner told the ACT Supreme Court in an emotional impact statement.
"Now I am your rape victim."
While her perpetrator previously admitted to sexual intercourse without consent, prosecutor Morgan Howe said the man had also noted being in a relationship and "therefore, effectively, consent being assumed".
Sentencing proceedings for the 52-year-old rapist, who is not named for legal reasons, began on Wednesday.
According to agreed facts, the pair met online on "Canberra Singles", moved in together, but eventually broke up.
When the man stayed over one night a few months later, amid attempts to patch things up, the victim awoke to him pushing her onto her side before having sex with her.
"That occurs before any conversation," Justice Louise Taylor said, noting the woman could not have consented while she was previously asleep.
"What are you doing?" the victim asked.
The man did not stop and instead responded: "Just relax."
In her impact statement, the victim described feeling scared at all times since the sexual assault and fearing hearing the man telling her to relax at night.
"You were supposed to be my soul mate, my best friend and confidant. You were supposed to be my protector, the one who chased the monsters away when I was having a bad dream," she wrote.
"I never imagined that you would turn out to be the monster I should have run away from."
In court, Legal Aid lawyer Edward Chen said there was no evidence suggesting his client knew the woman was not consenting. He submitted the man was instead reckless about consent.
Mr Chen asked the court to consider sentencing the man to a community-based prison term and said it would be "unnecessary and harmful to the community" to lock him up due to his good rehabilitation prospects.
"Even though there is limited insight shown by the offender ... he only needs to learn what consent is once," the defence lawyer said.
"He appreciates acutely what needs to be done in the future."
But Justice Taylor pushed back, noting the man's inability to articulate what harm had come from his crime to a pre-sentence report author reflected a lack of insight.
The prosecutor, who asked for full-time custody, said the only reasonable inference was the man knew his former partner had been sleeping, and therefore not consenting, before the sexual act.
"It won't happen again I promise," the rapist messaged the victim the day after the assault.
He is set to learn his fate in September.
- Support is available for those who may be distressed. Phone Lifeline 13 11 14; 1800-RESPECT 1800 737 732; Canberra Rape Crisis Centre 6247 2525; ACT Domestic Violence Crisis Service 6280 0900.
