An insider claimed, "they've been together for a while now" before noting, "it's been a year of them dating, possibly closer to two."
The source also revealed that the lovebirds, who are very private about their relationship, live together in a house they purchased.
A document shows that David and McCormick bought the house in February in his hometown, Pittsburgh, for $450,000. The property that features four-bedroom and four bathrooms is located in the tree-lined community of Regent Square on the East End of the city.
Their neighbor told the outlet the couple "seem like nice kids" and that "they keep to themselves."
What is fascinating about their relationship is their past dating history.
Cazzie used to be in a relationship with the Saturday Night Live star, who then moved on to date and became engaged to Ariana Grande.
Before becoming his fiance, Grande was previously in a relationship with Mac Miller, who passed away while Grande was engaged to Davidson.
According to reports, Cazzie developed a bond with Miller after their exes got together.
"Caziie and Mac never met, but started speaking because of Ariana and Pete's relationship," a source told Us Weekly. "[They] leaned on each other."
The daughter of comedian Larry David reportedly reached out to Meyers to send her condolences after learning about Miller's death. The Self Care rapper died at his home on Sept. 7, 2018, from an accidental overdose of fentanyl and cocaine at 26.
Cazzie later hung out with Miller's mom, Karen Meyers, in which she shared a photo of Meyers with her fans via Instagram Story ahead of the 61st annual Grammy Awards in 2019.
An informant added, "Cazzie and Mac's mom have become extremely close and talk almost every day. Mac's mom loves her."
This situation might explain how Cazzie ended up meeting and eventually dating Miller's brother.
The source told Page Six, "Mac's family loves Cazzie. Really it's no surprise she ended up with his brother, She's a beautiful beacon in what had been an intensely tough period of navigation."
Cazzie and Pete dated for two years after being first romantically linked in May 2016. Meanwhile, Grande went out with Miller for almost two years before they parted ways in May 2018.