How do we know? Because Bella called him out for it!
While recording an Instagram story to say good morning to her fans, she was distracted by Mod's phone that was chiming not stop with alerts.
"Okay, you know what? Someone seems popular..." she says. In the next clip, Bella uses the 'superzoom' effect to show that the notifications Mod was getting were from the dating app, Badoo. The app boasts that you can "chat, date and meet with over 330 million people."
Bella wrote on the clip, "When your boyfriend still has a dating app on his phone..."
Well then... that seems normal.
However after Bella uploaded the clip, she seemed to move on and not mention it any further.
It comes after Bella was kicked out of her hotel room with Mod in Los Angeles while promoting her new movie Assassination Nation, when they were caught with weed.
"They were seen rushing out of the hotel hours before the premiere," an eyewitness told Page Six. "There were so many bags, they needed a trail car to carry them."