“There was nothing to split from as it has been casual,” a friend of Affleck’s tells PEOPLE.
The end of the pair’s brief relationship comes just days after the two took a romantic vacation to Montana over the weekend, where Sexton, 22, posted a shot of Affleck, 46, on her social media for the first time.
“He enjoyed being with her but is working on himself, and being together with her at this time is not something that works,” the friend adds. “He will date in the future, but for now his focus is on his sobriety, family and his next project.”
The actor and the Playboy model first seen together at a cozy dinner at Nobu on Aug, 16, less than a week before Affleck checked into rehab seeking treatment for alcohol addiction on Aug. 22.
Days after Affleck checked into rehab, Sexton was seen driving the actor’s SUV and even visited him at the treatment centers during his stay. They were then seen together at his house shortly after he completed his treatment and went on vacation together later that week.
The actor posted a lengthy statement on his Instagram the day before their Montana getaway where he revealed he is now continuing outpatient care after wrapping up his 40-day stay.
“The support I have received from my family, colleagues and fans means more to me than I can say. It’s given me the strength and support to speak about my illness with others,” Affleck said in a statement. “Battling any addiction is a lifelong and difficult struggle. Because of that, one is never really in or out of treatment. It is full-time commitment. I am fighting for myself and my family.”
Affleck shares three kids — Violet, 12, Seraphina, 9, and Samuel, 6 — with ex Jennifer Garner.
This article originally appeared on our sister site PEOPLE.