"There is absolutely no wedding talk or planning going on," a source close to the couple told RadarOnline. "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 relationship is definitely at an impasse," added the source. "Either it's going to fizzle out, which seems likely, or they get married."
On 11 February the Along Came Polly star spent her special day with best friend Courtney Cox, while Justin remained in New York.
The Friends co-stars were spotted dining with Tobey Maguire's wife Jennifer Meyer and Jennifer's hairstylist Chris McMillan at the trendy Soho House in Los Angeles.
Jennifer also chose to stay in LA while Justin attended Philip Seymour Hoffman's Manhattan funeral on 7 February.
Justin is currently working on new HBO show The Leftovers in the Big Apple and was seen filming on set during the day of Jennifer's birthday. Later that night the director and screenwriter attended the Deth Killers of Bushwick store launch party in downtown Manhattan with Orlando Bloom, who separated from his wife Miranda Kerr late last year.
Fans will be eager to see if Jennifer and Justin attend the Oscars together on 2 March as they did in 2013.