Police say thieves broke into the New York City home of the fashion designer, who gained fame when she dated comic Jerry Seinfeld, and stole $1.5 million worth of jewelry.
Shoshanna Lonstein Gruss tells the New York Post she is heartbroken and feels "beyond violated" by the burglary.
The 41-year-old Gruss discovered the break-in Tuesday when she returned to her Manhattan home from a weekend at the beach.
She says she lost "lots of sentimental stuff that can't be replaced."
Gruss and Seinfeld were involved in a four-year relationship that started in 1993 when she was 17 and he was 38.
Gruss went on to a career as a designer of swimsuits and dresses.
She married Round Hill Music CEO Joshua Gruss in 2003. They divorced in 2014.