News broke on Wednesday that Bethenny Frankel was exiting the Bravo series

Bethenny Frankel‘s shocking departure from The Real Housewives of New York City was a “sudden decision,” a source tells PEOPLE — one that has left her Bravo castmates feeling “a bit lost.”

“Filming began hours after the announcement came out and it really threw everyone for a loop,” the source says about Frankel’s surprising exit this week.

“Usually before a season, these women have some idea what the next few months will look like based on the dynamics of the group, but this has left everyone a bit lost,” says the source.

According to the insider, “most of the folks in production” also thought Frankel would return for RHONY‘s season 12, which kicked off filming Wednesday — the same day the Skinnygirl mogul, 48, confirmed that she was leaving the Bravo series for the second time.

Shortly after news broke, Ramona Singer told PEOPLE that Frankel “did not inform her costars” in advance of the decision.

But a day later, the source says that “Bethenny reached out to many of her former costars Thursday night individually” and that “the conversations between her and the cast were nice and supportive. Everyone wishes her well.”

Bethenny Frankel
Bethenny Frankel
| Credit: Cindy Ord/Getty Images

“She explained it was a very sudden decision. Bethenny didn’t even consult [boyfriend Paul Bernon] about it,” the source says. “She really listens to her heart and said she felt like it was the right time to take a leap and jump into this next adventure.”

As to how Frankel is handling her decision, the source says “she’s feeling very emotional about it, but knows that you can only win at life when you swing big.”

The mother of one joined the Bravo reality series in season 1, but exited during season 3. Frankel later rejoined during season 7 and has starred on the show since.

The source also tells PEOPLE that with a spot open on the cast, there is a possibility of a new lady getting to hold an apple for season 12. “A few women had been previously testing for a spot, one of which is Leah McSweeney,” the source says. (Bravo would not comment on casting when reached by PEOPLE.)

On Thursday, Entertainment Tonight reported that McSweeney, a 36-year-old mother and entrepreneur and a friend of Tinsley Mortimer, was rumored to be joining the series.

But the source says that “reports that she’s a new Housewife are very premature — they’ve been known to downgrade people if they don’t gel with the group, like Barbara Kavovit last year.”

“There’s also always a chance the network could bring someone else back, too,” the source adds. “Bravo rarely closes the door to those possibilities, and Bethenny’s high salary could open things up. No one really knows what’ll happen right now. And if they do, they’re not telling the cast just yet.”

However, the source says that despite Frankel’s unexpected exit, her departure “won’t ruin the show by any means.”

Real Housewives Of New York
The RHONY season 11 cast
| Credit: Bravo

In a statement to PEOPLE, and first obtained by Variety, Frankel explained her decision to say goodbye to the show for a second time.

“I have decided to leave the Housewives franchise to explore my next chapter,” Frankel said.

“It’s time to move on and focus on my daughter, my philanthropy and my production partnership with Mark Burnett, producing and starring in shows which represent a shift in the conversation for women,” said Frankel, who is mom to 9-year-old daughter Bryn, whom she shares with ex Jason Hoppy.

RHONY Reunion
Bethenny Frankel
| Credit: Heidi Gutman/Bravo

“With the changes in modern culture, I want to highlight the strength, confidence and unstoppable power that women have. My experience at Bravo has been an incredibly magical ride,” she continued. “I am so grateful to them for highlighting my entrepreneurialism and allowing me to pave the way for many women to achieve their goals. I am excited for my future. The best is yet to come.”

Frankel also shared a lengthy message on Instagram, where she thanked her fans for their support, and told them to “stay tuned, you haven’t seen the last of me. There are many amazing things to come.”

Season 12 of The Real Housewives of New York City is expected to premiere next year.