Karl Stefanovic's children found out about his new relationship when they saw paparazzi pictures of him kissing Jasmine Yarbrough on a super yacht and then splashed across the front page of a Sunday tabloid.
"At no point before it was released in the media did Karl tell [his wife] Cassandra or the children he was in a relationship and that he wanted his girlfriend to meet them," a source told Fairfax Media on Tuesday.
"He has still not talked to his children about it and they were shocked by his public display of his relationship."
Meanwhile, Stefanovic's wife of 21 years, Cassandra Thorburn, whom he split from in August last year, is said to be "happy herself but concerned for their children" - Jackson, 17, Ava, 11 and River, 10.
The pictures published in The Sunday Telegraph show the Channel Nine Today show host, 42, kissing Yarbrough, a Brisbane-born model and shoe designer, 33, as they sailed around Sydney Harbour.
While the rest of the attendees mingled, Stefanovic and Yarbrough lay together on the bow of the luxury vessel.
The pair are said to have met on a lavish boat cruise in December and Stefanovic is believed to have flown to Los Angeles to spend time with Yarbrough over the Christmas holidays.
Yarbrough is based in LA where she runs shoe business Mara & Mine with co-founder, Tamie Ingham.
Following the release of the pictures, Stefanovic returned to the Today show on Monday, but was absent by Tuesday.
According to a Channel Nine spokesperson, he is currently taking time off from his morning gig to film This Time Next Year for the network. His sister-in-law-to-be Sylvia Jeffreys will fill in for him alongside co-host, Lisa Wilkinson, this week, while Tim Gilbert will take his seat next week until Stefanovic returns. Nine did not specify when that would be.
In the past when he would double job for the network, he would usually work evenings and weekends on the second show, while ensuring to be back on Today by morning.
It's an unusual move for Nine to pull the presenter from the air, especially at a time when they are head-to-head with rivals, Seven's Sunrise in the ratings.
After his split from Thorburn, Stefanovic was briefly linked to food blogger Sofia Levin, 27. However Levin, who is engaged, denied any relationship between them.
Fairfax Media has asked a representative of Karl Stefanovic for comment, but they did not immediately respond.
If you know more, email amy.croffey@fairfaxmedia.com.au.