"Girls" creator Lena Dunham and musician boyfriend Jack Antonoff are breaking up after five years together. A rep for the actress said the split, which took place in December, was "amicable."

"Jack and Lena were growing apart and it just made sense for them to end their relationship where it was," a source told E! News.

Dunham, 31, and the Bleachers frontman, 33, met in 2012 on a blind date set up by Antonoff's sister and comedian Mike Birbiglia. Their relationship was chronicled extensively on social media and in October, Dunham posted an Instagram pic highlighting their "5.5. year anniversary."

Also that month, Dunham wrote an essay in Variety praising Antonoff, who was also a member of the band .fun and has produced songs for Taylor Swift, Lorde, Pink, and St. Vincent. "It's safe to say that before Jack my life was full of far fewer sights. He showed me the importance of making political statements using your public platform. He showed me the joy of collaboration."

The couple had previously talked about not getting married until it was legal for same-sex couples. But even after marriage equality became a reality, Dunham indicated a wedding was likely not in the cards. In November, she joked that she believed Antonoff was planning to propose,