Radar Online reported Friday that Aniston, 45, and Theroux, 42, have "put their wedding on hold" after months of separation strained the relationship.
"Justin asked Jen to come to New York City but she declined, citing the cold weather. She wanted to be in sunny Southern California with her friends," a source said.
"It’s absolutely indicative of the status of Jen and Justin’s relationship. There is absolutely no wedding talk or planning going on. Publicly the couple is saying it’s because they are just too busy with work, but if they wanted to get married, it would happen."
The bicoastal couple have been dogged by break-up reports since they got engaged.
But they haven't been seen publicly since their New Year's trip to Mexico and more recently, he didn't join her for her birthday in Los Angeles.
"The relationship is definitely at an impasse…either it’s going to fizzle out, which seems likely, or they get married," Radar sources added.