Lena Dunham has revealed she cheated on Jack Antonoff during the final stages of their six-year relationship, describing a period marked by illness, strain and emotional upheaval.
In her forthcoming memoir Famesick, the Girls creator reflects on how chronic pain and the treatment that followed, which placed increasing pressure on the relationship, affecting everything from intimacy to day-to-day life.
Much of the book centres on her health during that time, including the lead-up to and recovery from a hysterectomy to treat endometriosis.
As per Variety, Dunham writes that she developed a dependency on pain medication in the aftermath, which ultimately led her to seek help.
She recounts a particularly fraught moment between the pair, describing what she calls the “worst fight” of their relationship, which took place shortly after the surgery when he raised concerns about her reliance on medication.
His response, she writes, “was to go to the bathroom and angrily flush all my pills down the toilet, which necessitated a call to the doctor and a late-night trip to the pharmacy to get more so that I wouldn’t go into withdrawal — from any one of the drugs — overnight.”
Dunham claims Antonoff “spoke to me in ways I have never been spoken to,” leaving her with a desire “to be wanted”.
She writes that she contacted a former school friend and slept with him that same evening, later describing herself in the book as “an adultress”.
She also suggests that Antonoff may have strayed during the same period, pointing to the intense online speculation that surrounded his reported connection with singer Lorde — widely believed to be the “teen pop star” referenced elsewhere in the memoir.
The rumours, she writes, were “so convincing that they had me rethinking events that I myself had been present for”.
“I wasn’t paying attention, but the internet sure was,” she adds, referencing the public scrutiny at the time. Both Antonoff and Lorde denied the claims.
As the relationship began to unravel, the couple agreed to take a break while continuing to share a home, with Antonoff frequently away on tour.
Dunham writes that she initially maintained “careful boundaries”, but later questioned whether those boundaries were mutual.
“If I wanted to look, perhaps I may have seen that Jack was not observing them as closely as I was,” she reflects.
The Standard has contacted Jack Antonoff’s reps for comment.
The pair met in 2012, introduced by comedian Mike Birbiglia, as Dunham’s HBO series Girls was gaining momentum and Antonoff was achieving commercial success with his band Fun.
Speaking ahead of the book’s release, Dunham described the experience of their split as both painful and oddly entwined with Antonoff’s creative output.
“It was a unique privilege to have every breakup song you love written by your ex,” she told The New York Times.
“I feel blessed. I was a really late bloomer. That was my first. I felt like you fall in love with someone and then you’re together for the rest of your life. That ending was extremely intense for me.”
Dunham went on to marry musician Luis Felber in 2021, while Antonoff married actor Margaret Qualley in 2023.
