The pair were on and off for around eight years before finally parting ways for good in 2018.
The singer, 27, has now opened up about the romance with Bieber, 25, who is now married to model Hailey Baldwin.
During a candid chat with America’s NPR, she explained her song Lose You to Love Me – which features lyrics about a toxic relationship – is about Bieber.
She went on to say she felt like she’d been victimised during her time with the former child star, confessing: “It’s dangerous to stay in a victim mentality.
“And I’m not being disrespectful, I do feel I was a victim to certain abuse.”
Interviewer Lulu Garcia-Navarro then asked: “You mean emotional abuse?” and Gomez added: “Yes, and I think that it’s something that – I had to find a way to understand it as an adult.
“As much as I definitely don’t want to spend the rest of my life talking about this, I am really proud that I can say I feel the strongest I’ve ever felt and I’ve found a way to just walk through it with as much grace as possible.”
Gomez added of the song: “I’m very proud of it [the song]. It has a different meaning to me now from when I wrote it.
“I felt I didn’t get a respectful closure, and I had accepted that, but I know I needed some way to just say a few things that I wish I had said.
“It’s not a hateful song; it’s a song that is saying – I had something beautiful and I would never deny that it wasn’t that.
“It was very difficult and I’m happy it’s over. And I felt like this was a great way to just say, you know, it’s done, and I understand that, and I respect that, and now here I am stepping into a whole other chapter.”
The track features lyrics about a toxic relationship, openly accusing Bieber of tearing her down when they were together and replacing her within “two months” after their split.
She sang: “You promised the world and I fell for it. I put you first and you adored it. Set fires to my forest. And you let it burn…
“I saw the signs and I ignored it… I gave my all and they all know it. Then you tore me down and now it’s showing. In two months, you replaced us. Like it was easy.”
Gomez split from Bieber in March 2018, and in July that year he announced he was engaged to Baldwin and they married months later.
In September last year, Bieber opened up about his personal problems and admitted he had abused drugs, suffered form depression and treated women badly in the past.