She suffered minor bruising when he pushed her during an ensuing argument.
His partner sought refuge at the house of a neighbour who called the police. The man followed, waving a knife and telling the woman to go home.
He then calmed down and went back to his house.
A short time later, the neighbour saw the man holding his toddler out of a second-storey window before going back inside.
Judge Roy Wade today sentenced the man to two years intensive supervision.
"I will impose a sentence of intensive supervision to assist you in sticking to the straight and narrow.''
The man had battled drug addiction problems before and had recently completed a home detention sentence for another conviction, Judge Wade said.
The court was previously told the couple were under financial stress, and there had been little rest in the house in the lead up to the incident.
Outside the courtroom, the man said the incident with his son had been "blown out of proportion''.
"I was just being a bit rough with my son. It could have lead to worse consequences.''
The man was still in a relationship with the woman and was trying to work through the pair's issues, defence lawyer Adam Holland said outside court.
"He's in the process of trying to reconcile his relationship.''
