The court was told he made her write down every sexual encounter she had ever had and stopped her using social networking sites such as Facebook and Twitter after reading her messages.
Jurors were played a secret recording she made of him verbally abusing her during a row, in which he called her a "f****** slag", a "dirty vile whore", and a "f****** sex addict".
He said the recording showed him at his worst but denied all her other claims.
He told the court he had never attacked her in any way and had never hit anyone in his life.
Collins said he had only ever slapped Ms Larke to calm her down when she was self-harming, which he claimed she did, once gouging her wrists and threatening to kill herself.
Ms Larke claimed Collins attacked her in a hotel room in Miami in March last year.
Giving evidence to the court, Ms Larke said she had not shown her doctor her bruises because she did not want to get Collins into trouble.
"I didn't want to do it to Justin. He was the love of my life," she said.
Speaking from behind a screen, the recovering alcoholic described being terrified about Collins returning from a trip to Las Vegas because she had failed to attend one of two AA meetings which she had told him she would attend.
"I remember his ringing me and shouting abuse down the phone to me. I was petrified about him coming back. Absolutely petrified," she said.
Judge John Plumstead sentenced Collins to carry out 140 hours unpaid work within the next 18 months and he was also ordered to pay £3,500 in prosecution costs.
One juror was discharged late yesterday after eight hours of deliberations with the 11 remaining jurors deliberating for a further three hours and 46 minutes today after being given a majority direction by the judge.
Collins, of Kew, south west London, had claimed his seven-month relationship with Ms Larke, also 38, was "absolute hell".
"I thought she loved me and was crazy about me," he said.
"But it turned out only the second part was true."
He said Ms Larke, who moved in with him in January last year, was obsessive, jealous and possessive and would send him a "barrage" of text messages wanting to know where he was and who he was with.
The pair met when he hosted the Golden Joysticks Awards in 2006, and began an affair in 2007 to 2008 before splitting up.
The relationship resumed at the end of 2010 after the defendant's marriage to his wife Karen, the mother of his sons Archie, seven, and Harvey, four, broke down.
Collins and Ms Larke lived together from January to July last year in a deeply troubled relationship as she tried to overcome alcoholism, the court heard.
Ms Larke alleged Collins made her write down in a Pukka pad all her previous sexual encounters regardless of how graphic.
But he told the court he did not want to write the details down but Ms Larke dictated them to him and he believed it may have been a form of catharsis for her.
He claimed that it was she who was the jealous one, and when his appearance in the West End production of Rock of Ages was announced last year, she immediately accused him of having an affair with fellow performers.
Ms Larke was described as a "fantasist", with the court hearing she bombarded him with text messages declaring her love for him and questioning him about other women after she had left him.
