Kate Gosselin Says Jon Changed 'Overnight,' Praises Daughter Mady for Speaking Out Against Him

The drama between Kate and Jon Gosselin continues.

In more of Kate's recent tell-all interview, she claims her ex-husband transformed suddenly before their 2009 split, and says she's still shocked about their divorce.

Meanwhile, Jon exclusively told ET on Wednesday that he's "very upset" about Kate's recent comments about their eight children, including the revelation that 12-year-old Collin -- who Jon recently admitted to ET he hasn't seen in two years -- is enrolled in a program away from home to help him cope with "special needs."  "I love my children very much," Jon said. "I’ve always been there for them and I always will be. It’s shocking."

WATCH: EXCLUSIVE -- Jon Gosselin Reacts to Kate and Twins' 'Shocking' Tell-All: 'I'm Very Upset'

In Kate's latest comments, the 41-year-old reality star claims to People that prior to their breakup, Jon’s behavior suddenly changed. Kate claims he began buying pricey items like motorcycles and cars -- as well as staying out late at night -- despite having eight kids and a wife at home.

"I really would have thought he'd have been here for the long haul," Kate reflects. "The weirdest thing is that overnight he became a different person."

"People closest to me thought I was crazy and making it up," she adds. "When they saw it for themselves, they were like, 'Whoa.' They saw the proof -- and then I saw all the letters from women saying, 'I've been there, too.'"

However, in an interview with ET earlier this month, 39-year-old Jon addressed the confusion viewers may have had in thinking he had such a drastic lifestyle change so suddenly after their split, given the time delay between real life and when the show actually aired.

"It's after we got divorced that things got crazy because I was going out, but the show was still showing us married, so, the public didn't know," he explained. "But what was happening was I was going out trying to live my life doing appearances and stuff, and then the next episode was us married with the kids and all that stuff."

As for Jon's now strained relationship with his twin daughters, 15-year-old Mady and Cara, Kate tells the magazine she's proud that Mady spoke up against her father. "He doesn't even know us," Mady told People, denying that she and her sister have been kept from him. "He should maybe spend some time thinking about why we don't want to see him, and maybe realize that if he ever does want a relationship with us, talking about us on TV is not the way to make that happen."

Kate says Mady is actually taking the "high road" when it comes to her father.

"She doesn't want to join his game," Kate says about her outspoken daughter. "At that age, to be able to locate the high road and stay on it, that just blows me away."

"It's not going to be an easy road -- anyone who grows up with a parent who is often absent is going to have issues to deal with," she also acknowledges.

Earlier this month, Jon told ET that Mady and Cara suddenly stopped coming to his house when they were around 12-13 years old. "I didn't question it. I was just like, 'Hey, do what you want, be with your friends,' and then it just became they're not coming," he said.

WATCH: Kate Gosselin Reveals 12-Year-Old Son Collin Is Away Getting Help for 'Special Needs'

He does, of course, want more of a relationship with his teenage girls.

"I mean, they're moving into womanhood," he said, pointing out that they're turning 16 in October. "I hope I can talk to them and develop a relationship in the future. But there's a lot of stuff that has to go on before that."

Watch our exclusive interview with Jon in the video below, in which he admits he hasn't seen all eight of his kids together in three years.