Though she's dealing with unimaginable heartbreak, the singer tells PEOPLE in this week's cover story, "I really, really want to prove to my kids their mother is strong." For Dion, work has become her safe haven. She'll be taking the stage at Sunday's Billboard Music Awards to receive the Icon award and performing a cover of Queen's "The Show Must Go On," a song title that had a strong significance in the couple's romance and work relationship.

"René always insisted the show must go on," the mother of three says. "You know what, I'm 48 years old and I lost the love of my life. I miss him a lot from when he was great but not when he was suffering. I cannot be selfish. You have to let people go. I feel at peace."

He was first diagnosed with throat cancer in 1999. In December 2013, doctors removed a tumor, but the cancer returned in 2014.


After learning that his cancer had returned for the third time, Dion says she and Angélil braced themselves for the inevitable. "I'm not the type of person who's going to say, 'I know he's going to make it,' " she recalls.

As the cancer got worse, speaking became very difficult for her love. "There were times when I was very, very scared and he'd write me 'The end is near, I feel it.' I would go back and say 'How can you say that? Are you in more pain?' Now I know it's possible for someone dying to feel when it comes," Dion says.

While living every day without her husband has been difficult, Dion says, "he left me with all of his strength. Every day we live with him, just not physically. I'm thankful that he does not suffer anymore."