Trust Issues

I think I'm having some trust issues. I'm always worried he's cheating on me now because I caught him a couple times in the past flirting with other girls on social media. I'm so paranoid I'm wondering why he brought his phone to the shower with him. It's bad and last time I caught him he said I could check his phone whenever but what am I supposed to do? Say let me look at your phone and make sure you're not cheating on me? I wish I could make these thoughts go away. Today I saw him commenting on a Snapchat photo of a girl wearing a dress and it seemed like he was trying not to let me see it. Am I just paranoid or should I be worried?