Oscar Blackall, 20, broke down in tears in the dock as the judge described how he had become obsessed with knowing where Alyshia Connorton was at all times.
Reading Crown Court heard how he had also lost his temper when she decided to watch a film by herself in a different room, and deliberately broke her laptop by twisting it.
Judge Emma Nott told Blackall how he had taken up a hammer and ‘repeatedly hit her with it in a methodical manner’ in an attempt to force her to give up her log in details.
She said: ‘Each time you asked her to log in to Facebook so you could monitor her activity.
‘Each time you hit her harder for your wholly unreasonable demand. By the time she was kicked she was curled up on the floor.
‘Having been tortured enough she gave you the details and you were satisfied with what you saw and let her go but unfortunately for you you went to her place of work and started shouting at her and you were arrested.
‘While it is right that you caused no fractures, the sustained assault with a hammer left bruising followed by kicking, effectively leaving the victim black and blue.’
Housemate stabbed by teenager for asking him to be quietBlackall’s defence lawyer told the court that the defendant had already served 55 days in custody, claiming there were ‘no serious injuries’ from the attack in Newbury, Berkshire.
But the judge rebutted his statement, saying: ‘It is a quite deliberate sustained assault with a hammer and he finished it with his feet. There was a multiplicity of injuries, how is it anything other than greater harm?’
She added: ‘This beating mercifully did not cause anything other than soft tissue damage but she had to be checked at the hospital and given head injury advice, she was left with a headache unsurprisingly.’
In a victim impact statement, Ms Connorton wrote that Blackall was a ‘greatly intelligent, caring person with an incredibly bright future’ and asked for him to receive a lenient sentence.
She said: ‘We have been together for so many years, what he has done is completely wrong but I have no ill will towards him and I do believe he has taken responsibility for his actions.
‘This said he does need help. I would like him to receive anger management which is enough.’
He was told by the judge: ‘The fact that she had multiple injuries over her body means it is classified as greater harm but in any event it is a clear prison sentence through her vulnerability at being in her own home and the sustained nature of the attack.
‘There are mitigating factors such as your previous good character and the fact that you are just 20-years-old so you have youth on your side, but I am not satisfied that you are truly remorseful for what you have done.
‘The victim statement shows her ongoing love for you and she wishes that you get help, she feels that you have been punished enough.
‘But the court must sentence you for what you have done and the risk that you pose. Your use of the hammer in a menacing manner to get what you wanted shows great harm.’