The court heard that the relationship between Riley and his victim, which began in 2013, soon began to break down when he became jealous and obsessive and began stalking her.
Police served a safety order on Riley after the victim complained she had received threatening text messages from him.
That was followed by a trespass notice, and another safety order, which Riley ignored.
Riley was violent and manipulative towards the victim on numerous occasions, including strangling her on a regular basis, Judge Thomas Ingram said.
On at least four other occasions the victim genuinely thought she was going to die, as she desperately fought to get away from the prisoner while he squeezed her carotid artery.
Over a prolonged period of time, Riley subjected the victim to repeated physical and verbal abuses, including kicks, punches, spitting in her face and repeated threats to kill her, as well as threats to kill her parents and brother, the court heard.
This included two instances when Riley held the victim captive in her home.
Riley bombarded the victim with flowers and hundreds of text messages to try to get the victim to agree to get back with him, including after his arrest.
Acting Crown Solicitor Anna Pollett argued a jail sentence of at least seven years was warranted given the serious nature and duration of Riley's offending.
Ms Pollett said psychological reports before the court confirmed the prisoner was at high risk of reoffending, particularly against women he had an intimate relationship with.
The Crown sought a minimum non-parole period of half of Riley's sentence both as deterrent for him and protection for the victim and the rest of community, she said.
Riley's lawyer Mark Ryan urged the judge to impose concurrent sentences for the "less serious" charges.
Mr Ryan said despite Riley's intention to appeal his convictions, he was keen to seek rehabilitation.
Despite earlier denials, Riley admitted to Judge Ingram he had been physically abusive to the victim.
Ms Pollett said she was "highly sceptical" of the timing of the prisoner's admission.
Judge Ingram said this did not appear to be some kind of "Come to Jesus moment" but Riley finally acknowledging his wrong doing, and he deserved some credit for doing so.
Despite the victim becoming a "hostile witness" at Riley's trial and standing by him, he was satisfied the jury reached the correct verdict, the judge said.