I'm think going to snoop through my boyfriend's phone a second time
What makes it okay for you to snoop through your boyfriend's phone again for the second time?
Because I want to know if he's cheating on me.
Your snooping might prove to you that he might or might not be cheating, but it is so sneaky of you to do that. Trusting him is not so easy but also is more normal than wanting to check up on him all the time. If he is cheating then tell him to be honest about it, so you won't have to go through negative ordeals after finding out while snooping.
I think he's cheating on me because he's too nice to me. I can't just drop my boyfriend for no reason.
Just because he's nice doesn't mean he's trying to cover something up. I believe you just need to come clean about your mistrust, because it's best to be honest after snooping. He will understand if you talk, and you can clear up all of the anxieties in your relationship.