"The Girls" creator and Antonoff, who met on a blind date in 2012, broke up in December, reported E! News.
"It was mutual. Jack and Lena were growing apart and it just made sense for them to end their relationship where it was," the website said quoting a source.
The couple's split is said to be amicable.
"They want the best for each other no matter what. They are both moving on," the source added.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)