Following their break-up, the 35-year-old sent a cryptic tweet to music manager Jack, 26, suggesting there was more to come from the fall-out.
After Jack asked his Twitter followers to support Caroline in the Strictly Come Dancing finals, she replied: "Easing your guilt? Fill yourself with glee Jack."
Now it's been reported there was a message in her response, suggesting Jack had been linked to 28-year-old US actress and Glee star Dianna Agron.
According to The Sun, Jack and Dianna 'became friendly' while he was working across the pond and had several nights out together.
An insider said: "[Caroline] has really been suffering but is putting on a brave face for the cameras.
"It was hard for her to find out about Dianna – especially as Jack was the man she thought she was going to marry. Their split was a painful decision and has put a massive strain on the whole Strictly process for her.
"But having to concentrate on eight-hour rehearsals every day is helping take her mind off things. She is just getting on with it, like everyone else who has been in the same situation has had to do."
Caroline and Jack were together for a year and a half, and she previously confessed to telling him she loved him on their second date.