Southern Charm 's Kathryn Dennis Says Thomas Ravenel Hid Baby News from Her: It's Not 'Normal'

Southern Charm's Kathryn Dennis Has Been Dating Chleb Ravenell for 'a Few Months': Source

"They have good chemistry together," a source tells PEOPLE

Thomas Ravenel is full of surprises.

During Thursday's episode of Southern Charm, Kathryn Dennis learned that her ex was expecting a baby with another woman — just as she was starting to consider giving their relationship another try.

"I guess it could work out, I wonder if it will," said Kathryn, who was temporarily living with Thomas at the time while her home was under construction. "The thought has run through my head more than a few times."

"He's the father of my kids, so that 'You never know' thing is always going to be in the back of my head," she added. (Kathryn, 29, and Thomas, 58, share daughter Kensie, 6, and son Saint Julien, 4½.)

But that idea was promptly shut down when she got an unexpected text message about her ex while at dinner with friends. Rattled, Kathryn pulled her longtime friend Danni Baird aside to tell her the news.

Charles Sykes/Bravo; Rebecca Miller/Bravo

"Thomas got a girl pregnant and she's having the baby. I just found out," Kathryn told her. "It's happening."

Asked how far along the mom-to-be was, Kathryn said, "probably six, seven months."

But according to Kathryn, she didn't find out from Thomas — instead, her lawyer broke the news to her. "My lawyer found out and he confirmed it," she said.

RELATED: Southern Charm's Kathryn Dennis Finds Out Thomas Ravenel Is Having Another Baby — 'It's Happening'

Kathryn Calhoun Dennis/Instagram Kathryn Dennis and Thomas Ravenel with their two children

RELATED: Inside Southern Charm Star Thomas Ravenel's Political Rise and Fall

Back at the table with the rest of the group, Kathryn revealed that she confronted Thomas about rumors that he was expecting another child — and said he outright denied it.

"A while back, I found a positive pregnancy test at his house and he was like, 'Wasn't me, must have been someone else,'" she said. "I had heard that he had been spotted at an OBGYN with a girl who was showing."

"It's not a normal thing," she added.

During a confessional interview, Kathryn said she felt betrayed by the news. "I cannot believe I've been living in the house with this man who has been hiding a secret that he has a child on the way," she said. "Meanwhile I'm like, 'Oh, maybe if we got back together, this is what it would be like.'"

RELATED: Examining Southern Charm Star Thomas Ravenel's History of Assault Allegations

"My family, a piece of it was taken away. It's no longer the Ravenels," she told the group. "I don't know what the next step is."

Thomas welcomed a son, Jonathan Jackson, with ex-girlfriend Heather Mascoe on June 29.

Thomas Ravenel/Twitter; Inset: Charles Sykes/Bravo/NBCU Photo Bank/NBCUniversal via Getty Thomas Ravenel's son Jonathan

"Meet Jonathan Jackson Ravenel. One 5 weeks old," he tweeted in August, sharing a photo of the newborn.

Thomas and Heather, 38, were first linked last April, though they had split by August, a source told PEOPLE. She has two children from a previous relationship.

Southern Charm airs Thursdays (9 p.m. ET) on Bravo.