Atkinson told the victim "to get out of his house", but the assault stopped when the two children needed attention.
The victim's parents then phoned, and Atkinson "became angry again" and started being "verbally abusive".
The victim ended the call and fell on the bed, where Atkinson kicked her in the legs and the back of her head.
He "blamed the victim for the assault", Judge Cameron said.
Atkinson called police, saying his former partner had arrived with the children and refused to leave.
Police arrived and found the victim in a "distressed" state.
Then, on October 17, while on bail for the first assault, Atkinson again assaulted the victim.
She was preparing lunch and asked for help, Judge Cameron said. An argument started, and escalated to Atkinson throwing her to the ground. The victim managed to get up and go to a neighbour's house to call police.
Atkinson pleaded guilty in court to male assaults female and assault with intent to injure.
He has previously been convicted for assaulting the same victim. Judge David Cameron sentenced Atkinson to 11 months in prison, with six months of release conditions.