I looked through my exs phone just now. It's not the first time
Why are you snooping on him?
He cheated on me.
I'm sorry he did that to you.  He betrayed your trust.  However, you're doing the same thing to him by snooping through his phone and I think both of you should be more honest with eachother.
What's the point of two people being honest online.
It always better to lead with honesty. If you don't trust each other, maybe it is time to break up.