Philip Seymour Hoffman's Lon​​gtime Partner Speaks out About His Death

Philip Seymour Hoffman's longtime partner, Mimi O'Donnell, has spoken out about the late actor's heroin addiction and relapse, which "terrified" her.

"As soon as Phil started using heroin again, I sensed it, terrified," the costume designer wrote in an essay for Vogue. "I told him, 'You're going to die. That's what happens with heroin.' Every day was filled with worry. Every night, when he went out, I wondered: Will I see him again?"

Hoffman struggled with addictions to heroin and alcohol until his early 20s. Before the actor began using again in 2012, Hoffman and O'Donnell had a great life.

"If I were to take a snapshot of how things were before they changed, it would look like this: We were living in the West Village," O'Donnell wrote. "We had three healthy kids. Phil's career was skyrocketing. He and I were still collaborating on theater and films, and I had started directing plays. We had wonderful friends. We had money. We were both so aware, since we came from middle-class backgrounds, of how much we had."

But things changed in 2012. His longtime therapist died and he had a "falling out" with his Alcoholics Anonymous friends. As his film career succeeded, he left behind his AA group.

When Hoffman suggested he would try to have a drink again, O'Donnell knew it was a "red flag."

"He started having a drink or two without it seeming a big deal, but the moment drugs came into play, I confronted Phil, who admitted that he'd gotten ahold of some prescription opioids," O'Donnell recalled. "He told me that it was just this one time, and that it wouldn't happen again. It scared him enough that, for a while, he kept his word."

Hoffman starred in a production of Death of a Salesman that year, and O'Donnell believed it kept him from using drugs. He was drinking after evening shows, but was "otherwise clean." When the show closed, O'Donnell's worst fears were realized when she learned that he was using heroin again.

Hoffman tried to stop and O'Donnell checked him into rehab. After the rehab stint, he started using again within a day or two of leaving.

The actor went back to rehab again, and he was sober for three months. But he started using heroin again.

While the Capote actor filmed The Hunger Games in Atlanta, he and O'Donnell were planning another rehab stint after it finished.

"It happened so quickly," O'Donnell wrote of Hoffman's death. "Phil came home from Atlanta, and I called a few people and said that we needed to keep an eye on him. Then he started using again, and three days later he was dead."

"It's been almost four years since Phil died, and the kids and I are still in a place where that fact is there every day. We talk about him constantly, only now we can talk about him without instantly crying," O'Donnell wrote. "That's the small difference, the little bit of progress that we've made. We can talk about him in a way that feels as though there's a remembrance of what happened to him, but that also honors him."

Hoffman died on Feb. 2, 2014 at age 46. He had three children with O'Donnell, Tallulah, Cooper and Willa.

Photo credit: Yui Mok - PA Images/Getty