How Jim Carrey is coping after his ex-girlfriend's suicide

It's been nearly a year since Jim Carrey’s ex-girlfriend committed suicide, and a source says the actor is slowly moving on with his life.

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The actor’s ex, Cathriona White, 30, overdosed on prescription pills in September 2015, and was found with a note addressed to Jim, according to her autopsy report.

"He’s doing good now but he’s still very much affected by her death," a source tells PEOPLE. In Cathriona's letter, she explained why she was ending her life and apologized to the actor, with whom she had split a week before.

Cathriona's suicide "was extremely difficult for Jim. There was a lot of sadness and many 'what if' questions," says the source. "It hit him very hard. He went through a long grieving period."

Jim, 53, and Cathriona, an Ireland native, first met on a film set in 2012 and had been dating on and off ever since. According to the autopsy report, Dennis Bradshaw, a friend of White’s, told officers that she was normally happy and upbeat, but was prone to get "really down."

The Carrey source says the actor "understands depression, it’s Jim. He has struggled with this, too. That’s why he and Cathriona did work. They both shared these up-and-down personalities."

Though Jim is now trying to move on, he remains in contact with White’s family. "He really felt for them," adds the source. "They weren’t able to grieve in peace and it was all a spectacle. He felt terrible about it. He did what he could to help her family out."

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