Rumer, 25, and actor Blair, 29, first debuted as a couple when they stepped out together in August 2012, reported Us magazine.
The 'Sorority Row' actress is allegedly spending time with mother after her break up.
"Rumer seemed really happy that her mother had come out to support her," a source said.
The pair were last spotted together at Warwick in Hollywood on Octeber 24.
Rumer and Blair first met through mutual friends and seemed to have had a positive influence on each other from the start.