The couple reportedly was out and about together in Los Angeles less than a month ago, but Dawson pulled the plug.
"She broke up with him," a source said. "She was the one who ended it."
The source said Dawson and Schreyer, a French DJ by trade, were "always in separate places because of their careers" during their romance that began in 2008.
Celebrity Couples of 2014 [PHOTOS]