Affleck began by slamming the "f**king horrible lies" that were printed amid his and Garner's breakup, before sharing how it actually went down from his point of view.
"The truth was, we took our time, we made a decision, we grew apart. We had a marriage that did not work. This happens," he said. "It is somebody I love and respect, but to whom I should not be married any longer."
"And then we said, 'You know what? We tried. We tried, because we had kids,'" Affleck continued, "and then both of us felt like, 'We don't want this to be the model that our kids see of marriage.'"
Had they not ended their relationship, Affleck believes that they "would have ended up at each other's throats" and that he "would probably still be drinking."
"That was part of why I started drinking alcohol, I was trapped," he said of his marriage to 49-year-old Garner. "I was like, 'I can't leave because of my kids, but I am not happy. What do I do?' What I did was drink a bottle of scotch on the couch, which turned out not to be the solution."
When it did come time to end things, Affleck said that he and Garner "did it amicably."
"Did we have moments of tension? Did we have disagreements over the custody? Was stuff difficult for us? Did we get angry? Yes," he admitted. "But fundamentally it was always underpinned with respect. I knew she was a good mom. I hope that she knew that I was a good dad. I was. I had to get sober, I knew that too and I acknowledged that. I said, 'You're right. I've got to quit drinking.'"
Affleck has previously been open about his battle with addiction, something his father, Timothy Affleck, likewise struggled with but has now been sober for 30 years.
"Getting sober actually helped me be more forgiving and recognizing, 'You know what? He had it f**king rough too,'" Affleck said of his dad. "What happens when you get sober is you stand around and you see a lot of people and you develop empathy for [people] who have done the same f**king thing."
As for his own sobriety journey, Affleck noted that "the cure for addiction is suffering."
"You suffer enough that something inside you goes, 'I am done,'" he explained. "I am lucky because I hit that point... when I felt as if [my addiction] impacted [my kids]. I recognized it. It was the worst day of my life," he said. "I made amends. For a while, I thought it was temporary, 'Maybe this feeling is going to go away.' But since that day, I swear to Christ, I have not ever wanted to drink once."
Earlier this year, Affleck and Jennifer Lopez reignited their early aughts romance. Watch the video below for more on their relationship.