It’s official: Katherine Heigl has left Grey’s Anatomy

“I am done,” the actress tells Entertainment Weekly in its new issue. “We just finalized our agreement. Everyone had been working really hard to find an amicable and gracious way of letting go and moving on. It’s sad but it’s what I wanted.”

In the end, Heigl decided to leave the hit ABC show because of her family — and not necessarily to advance her film career. “I started a family and it changed everything for me,” she says. “It changed my desire to work full-time.”

In Sept. 2009, Heigl and husband Josh Kelley adopted their daughter Naleigh from South Korea. She also took a three-month leave from Grey’s Anatomy to spend time with her family, an experience that made her want to focus on motherhood, she recently told PEOPLE.

“I think I’m just gonna try and keep it a little more mellow,” she told PEOPLE, “and be a little bit more of a mom, since that’s a big part of my life now. I took those three months off and I realized how very, very important is my family is to me and I want to be more available to them.”

Speculation had grown recently that the actress was planning her exit from Grey’s after she did not return to set following her maternity leave. “The details, the timeline of that — it’s all shades of gray,” a source told PEOPLE at the time. “The terms of her exit are still being sorted out.”

And if fans are expecting a big farewell arc, they may be disappointed. Heigl tells Entertainment Weekly that her Jan. 21 episode was her last — and that she is no longer appearing in the season’s final five episodes. “I know I’m disappointing the fans,” she tells EW. “I just had to make a choice. I hope I made the right one.”