E! reports that Grande was scheduled to perform at the F**k Cancer Gala at Warner Bros. According to Us Weekly, she pulled out of an appearance at a cancer benefit scheduled for October 13 for personal reasons.
Instead of Ariana performing at the event, Scooter "called in a favor" and had the host of The Daily Show, Trevor Noah, do a stand-up performance instead of Ariana.
Grande has recently shared on Twitter that she is going through a rough patch. The last time we saw them together was just last week.
Engaged since May - weeks after meeting - the couple is reportedly on good terms and they still "have love for each other".
Since then, the two have been through a lot, including Davidson's claims that he was getting death threats over their pairing and Grande's ex Mac Miller's death from an apparent overdose in September.More news: Hamilton edges closer to fifth title as Vettel crashes
Miller and Grande had been dating for over a year and a half before they broke up earlier this year.
Ariana shocked fans back in June when she announced Pete had put a ring on it just weeks into their whirlwind romance.
Putting aside the Swimming rapper's death, Ariana also experienced one of Britain's great tragedies when a suicide bomber murdered 22 people at her show in Manchester previous year.
Grande had previously defended her lightning-fast decision to marry Davidson, declaring, "Love is lit".