Theroux reportedly felt the pressure to leave New York and move into Aniston's LA mansion, but now he craves for his old lifestyle, Showbizspy reported.
"Even though Justin was blown away by Jen's charm, sexiness and power, he now feels they aren't compatible. The bloom is off the rose. He wants his old home, his old love Heidi Bivens and his old life back.
"Justin and Heidi still talk, and they are very supportive of each other. Justin feels she's handled herself with grace, never becoming nasty or vindictive though it was a total shock when he began seeing Jen behind her back while they were still living together," a source said.
Aniston began a relationship with Theroux last year and she sold her Beverly Hills mansion in July 2011 to move into a new house in Los Angeles with him.