The 37-year-old talent manager is now back on good terms working with the 'No Tears Left To Cry' hitmaker, but that wasn't the case a few years ago when she parted ways with her management team.
And Scooter has hinted that a ''sh***y boyfriend'' influenced Ariana to fire the manager, as after she broke off the romance, she ''saw the light'' and asked to get in touch with Scooter once again.
He said: ''I could have said a lot of stuff, and in fact my team wanted me to, because they were pissed. But I said 'We're not gonna say a word, and this is gonna come back around.' They were like, 'Never take her back!', but I just said 'Let's stay quiet and let our truth be our actions.'
''And when sh***y boyfriends leave, she starts to see the light on some stuff, and one day I got a phone call. She said 'Can I see you tomorrow?' and I said, 'No, I'm busy' - I actually couldn't, so I said 'I could see you Thursday' or whatever and I went over there and we had a very honest conversation.''
Scooter - who also manages Justin Bieber - thinks the experience made him a ''better manager'', because he feels more humble now that he understands his artists aren't worried about firing him.
He added: ''Where it made me a better manager, number one, it allowed me to know that I can be fired - I had never been fired before. It made me know that as much as you give to people in a service business - we do a lot of asset business, but this is a service business - you can never expect anyone to reciprocate. You have to do it for the right reasons, and if you get screwed over in the end, so be it, and hope you had a hell of the ride along the way.''
And the talent manager also believes the incident helped to give him and Ariana, 25, the ''strength'' to tackle the events of 2017, when the singer's concert in Manchester was targeted by a suicide bomber who killed 22 people.
Speaking to Variety magazine, he said: ''And that relationship we had, from being fired to getting back together, really gave us the strength for what we never imagined would come that following year.''
Just two weeks after the tragedy, Scooter and Ariana staged a benefit concert, named One Love Manchester, in the city to help raise funds for those affected.