Jennifer Lopez has a hit show on NBC, sings to huge crowds for her Las Vegas residency and is mom to adorable 8-year-old twins Max and Emme, but the superstar admits just a few years ago life didn't seem so rosy.
When she and Marc Anthony filed for divorce, "it was devastating and awful," she says in The Jess Cagle Interview with People and Entertainment Weekly's editorial director. "I think both Marc and I thought at the time we would be together for the next 40 years until we die."
Watch more of The Jess Cagle Interview with Jennifer Lopez on PEOPLE.com all this week.
Though Lopez, 46, calls the failed marriage "the biggest disappointment of my life so far," the star stresses the split was still the right decision for her.
"I felt like at that time I had lost my way a little bit, of who I was in trying to make the marriage [work]," says the Shades of Blue star (the show's finale airs March 31).
For more on Jennifer Lopez's gritty new show and her happy life now, pick up the latest issue of PEOPLE, on newsstands Friday.
"I had been married twice before and I didn't want this to be a failure ... I just put all my heart and soul into that and forgot who I was as an individual a little bit."
After she and Anthony called it quits, Lopez felt a sense of "empowerment," she adds. "It was the right thing."