A VICTORIAN man who told his transgender stepdaughter she should be happy he was having sex with her because no man would want her has been jailed for a decade after she secretly filmed his attacks.

The father of three, who cannot be named, forced himself on his stepdaughter up to three or four times a week between 2002 and 2015, and threatened to ruin her mother if she resisted.

County Court Judge Frank Gucciardo on Tuesday jailed the man for 10 years for his “utterly abhorrent” exploitation of a vulnerable young woman who was undergoing a transformation.

“You understood these frailties and exploited them,” the judge said, setting a minimum term of seven years.

The “unrelenting” offending started not long after his stepdaughter’s gender reassignment surgery.

“She felt pain and told you to stop, but to no avail,” Judge Gucciardo said.

The man told his victim he couldn’t help it because she’d become such a beautiful woman and forced himself on her, saying: “I know you’ve been wanting this since your operation”.

He also threatened to take her mum “for all she’s worth” if his victim said anything.

The man called his victim his second wife and reiterated his threats, causing her pain while saying he loved her.

“You told her repeatedly that her family hated her and she began to believe you,” Judge Gucciardo said.

The judge called the man’s behaviour “psychological manipulation of the highest order”.

He said it showed contempt for the victim for the guilty man’s own “vile sexual gratification”.

The incest ended after the woman secretly recorded her stepfather on her iPad.

He saw the device, accused her of trying to frame him and grabbed her by the hair before being interrupted by the arrival of her mother.

At that point the man said: “Your daughter wants it. She wants me to f*** her.” He then fled and police were called.

Initially, he tried to blame the woman for the sex acts.

His first police interview was a “rambling diatribe” about the victim’s violence, her desire to have sex with him, and the fact that he did it because he thought it was the right thing to do. The stepdaughter held a knife to his throat on one occasion, he claimed to police.

He later pleaded guilty to four counts of incest in the Victorian County Court.

The man, a foreign national, will be added to the sex offenders register for life and faces possible deportation upon his release from prison.