Justin Bieber and Selena Gomez got into a fight in the comments section of one of his Instagram pictures on Sunday, because why would you try to keep a fight between you and your ex private, right? Especially when the argument is over him posting too many pictures of his new girlfriend. But their super passive-aggressive "fight" just got really nasty Monday morning when she implied that he cheated on her.

Bieber posted a series of pictures of himself with his new lady love, model Sofia Richie (daughter of Lionel and Diana Richie). He then got a ton of negative comments (mostly about Richie), and captioned one last picture: