The journalist, who returned to the Today show at the start of the year, separated from Thorburn, his wife of 21 years and the mother of their three children, in 2016.
Five months following the separation, the Channel Nine presenter met shoe-designer Yarbrough, a decade his junior, while onboard a luxury cruise ship in Sydney.
They later went public with their relationship in 2017, when they were pictured in Bora Bora on James Packer’s yacht.
At the time, Karl’s detractors thought he had moved on from his marriage too quickly and their relationship was the catalyst for an onslaught of media attention, intense scrutiny and the ruthless intrusion of their personal lives.
"She’s been through so much. She’s been pilloried and accused of things that didn’t happen," Stefanovic said of his now-wife, who is currently pregnant with their first child together, in a new interview with Stellar magazine.
"It’s not her fault she fell in love with bugalugs, and the accusations were wrong about her stealing me from Cassandra. It’s rubbish and it’s hurtful.
"She’s just a beautiful, sweet woman from Queensland who runs a business and fell in love with me."