When she returned, Ratana "went at her again", pushing her to the ground, then pulling her back up again by her hair. He then punched her in the face again, Judge Crayton said.
She fell back to the ground, and Ratana grabbed her head and banged it against a large wooden pole several times.
"You clearly intended to cause her injury," Judge Crayton said.
"You have to understand that violence towards women, violence towards your partner, is utterly unacceptable.
"You have, fortunately, told this court that you want to take ownership, and you have taken ownership and you get credit for that."
He said Ratana had not been before the court for nine years.
He sentenced him to 150 hours of community work.