Romo reportedly dumped Simpson last week on the eve of her 29th birthday. They had dated for nearly three years.
"She is heartbroken," a source told People. "She loves Tony. But it's been difficult lately. He's busy with his career and she's getting ready to shoot her show ('The Price of Beauty.') They decided to part ways."
People.com said Simpson's publicist declined to say anything about the story and Romo's representative could not be reached for comment.
Simpson was previously married to singer Nick Lachey. They starred in a popular TV reality series called "Newlyweds: Nick & Jessica."
Lachey recently split up with his longtime girlfriend, TV personality Vanessa Minnillo.