I think he is faking it to show DJ how much she hurt him. His behavior is a bit off specially after what she did no guy would just go behind like this.
But i also think he's feeling bad about it. That day he spoke to avanti like that on purpose to rile her and create issues between her and DJ. But immediately after he looked like he felt bad.Also at the ghat that day when he was going to kiss DJ, he looked a bit hesitant as if he doesn't really wanna play with her feelings.Either way, it's all interesting!