Is he telling the truth?

A girl at my school told me my boyfriend of 2 years has been snapchating her best friend. He says he hasn’t and that I should trust him. I want him to show me his snapchat and prove to me he hasn’t. He is just getting mad at me and saying I need to trust him.

Is it wrong for me to want to see his snapchat to make sure he isn’t talking to her? or should i just trust him and believe he isn’t talking to her? or do you think he is talking to her?