Joseph Johnson threatened the woman – who was holding her ten-month-old baby at the time – with two knives during the incident on February 19.
Johsnon caused an injury to her stomach, repeatedly hit her in the face, and threatened to kill her after she told him she wanted to end their relationship.
In a bid to escape, the petrified victim left the baby in the property and jumped from the bedroom window, falling more than six metres onto the ground below.
As she lay injured, Johnson dragged the woman back inside, where she managed to break free and run to a nearby witness for help.
Johnson, 25, was jailed for seven years and three months.