The actress apparently felt that she has grown out of the relationship and there was no point mending fences when there was nothing left in it.
"It was Sonam who decided to call it off. There had been constant reports that the two had parted ways on and off. But this time it is for real and they have broken off," said a source.
"Tongues started wagging at producer Ronnie Screwvala's bash for newly-weds Vidya Balan and Siddharth Roy Kapur. Sonam who was present for the party avoided Punit like the plague. Both of them preferred to be in separate corners throughout the evening, the source added.
Reports also suggest that Sonam's mother Sunita was apparently not too keen about the relationship. Though Punit had made his debut as director in a Karan Johar production, he was keen to become an actor.
Sonam's busy shoot schedules and other commitments too aided in the couple drifting apart.
Speculations about the two began ever since they bonded well on the sets of their 2010 film I Hate Luv Storys that was Punit's directorial debut. Sonam was in the film along with Imran Khan. Love blossomed during the shoot schedule in New Zealand.
The couple never admitted to the relationship and there was always constant reports that they had separated. But every now and then Sonam and Punit were spotted cruising around Juhu's bylanes or at a multiplex catching up on the latest Hollywood release putting to rest all such talk. However off late they were having a lot of differences resulting in the relationship going kaput.