Ariana's former boyfriend Miller - who she split up from in May just before she got engaged to Pete - died on Friday (07.09.18) from a suspected overdose and the 25-year-old star was forced to turn off comments on her Instagram account when fans left nasty messages including ''This is your fault'' and ''You did this to him''.
Pete, 24, also wiped all pictures from his account.
While fans have hit out at Ariana over Mac's death; the star had been open about his 10-year battle with addiction, which began before he ever met Ariana.
He previously said: ''I love lean; it's great. I was not happy and I was on lean very heavy. I was so f**ked up all the time it was bad. My friends couldn't even look at me the same. I was lost.''
Ariana was also blamed for Mac's car crash less than a week after their break-up, when he fled the scene after wrecking his vehicle while under the influence of alcohol.
However, she hit back, insisting she was not his babysitter.
One fan wrote: ''Mac Miller totally his G wagon and getting a DUI after Ariana Grande dumped him for another dude after he poured his heart out on a ten song album to her called the divine feminine is just the most heartbreaking thing happening in Hollywood.''
And Ariana hit back, saying: ''How absurd that you minimize female self-respect and self-worth by saying someone should stay in a toxic relationship because he wrote an album about them, which btw isn't the case (only Cinderella is ab me).
''I am not a babysitter or a mother and no woman should feel that they need to be. I have cared for him and tried to support his sobriety & prayed for his balance for years (and always will of course) but shaming/blaming women for a man's inability to keep his sh** together is a very major problem.
''Let's please stop doing that. of course i didn't share about how hard or scary it was while it was happening but it was. i will continue to pray from the bottom of my heart that he figures it all out and that any other woman in this position does as well (sic).''
Miller - whose real name is Malcolm McCormick - dated Ariana Grande for nearly two years, before they split in May and she is said to be devastated by Miller's death.
A source told 'Entertainment Tonight': ''Although the two ended their relationship, Ariana always shared a deep connection with Mac and wanted nothing but the best for him. Ariana is very upset.''
Another source said: ''Despite their split, Ariana had always been supportive of his sobriety.''