A prison term at sentencing next month was inevitable, the judge said.
The court heard at the trial's outset on Monday that the victim, who had been in an on-off relationship with the man for some years, went to drop laundry at his shearing cabin in October last year.
She had the couple's three young children - all under the age of 7 - with her, but that did not cool tensions.
The defendant initially argued with the woman about the state of their relationship, which had recently ended, as she sat in her vehicle.
Then the man demanded they all enter his small room.
There he claimed the victim had been unfaithful to him and ordered her to tell him the truth.
Her denials were rejected and she tearfully recounted what happened.
''I was crying, my son was yelling at him telling him to leave mum alone, my daughter was yelling at him,'' the complainant said.
''So I lied to him and told him I'd slept with somebody else.''
The man helped put the children back into the vehicle and told them to stay there.
He had not finished with his ex-partner.
The defendant ushered her into his cabin, shut the curtains and locked the door.
After trying to stop the man removing her clothes, the victim ended up on the bed on her back.
She told the jury she held her hands over her eyes and wept throughout the ordeal.
When it had finished, the man told her to calm down before he let the children back in.
Later the same day, the victim told her friend what had happened and the woman called police on her behalf.
Judge Crosbie thanked the jurors for their service.
''Obviously you found the complainant a credible witness,'' he said.
