Started watching IPKKND and I’m kinda confused

I started watching ipkknd and the characters confuse me. Don’t get me wrong I love the chemistry between the leads but arnav is so confusing. One moment he is totally in love with Khushi and the other moment he is manhandling her. Like ik he has a traumatic past but isn’t this toxic behavior? I mean people have hyped this show a lot so I didn’t expect this. Also what is he? An Atheist? Does he believe in god or will he believe in god in the future? He is super hot but he confuses me a lot.