My boyfriend has broken my trust (need advice)

So for a while now my boyfriend will always take his phone with him and he will never leave his phone with me alone. I was at his place on Sunday and after coming back from his soccer game we were watching the voice on tv, I don't have the voice app on my phone but he does so I said to him can I have your phone to play on the app he said 'ok' but he had to be next to me and see what I was doing. When the voice ended I closed the app and just kept holding onto his phone he said 'what you doing' I said 'nothing what's the problem' I then ran from him and went in his gallery and saw a glance of a girl naked in his screenshot album before he snatched the phone from me I immediately had a heart attack i went to his room to get my stuff so I could leave he met me in his room. I said to him in tears 'what the hell is that I saw on your phone' he said nothing and to just forget about it I said 'no what is that Im pretty sure i know what I saw' I said 'you show me right now or i walk' he said 'I can't', he let me walk so he didn't have to show me the photo. I couldn't believe it. When I got home he wouldn't stop calling me and texting me. He's been giving me space now. I don't know how long he's had that photo for. He said in his texts he didn't want to tell me or show me because he knew it would hurt me and that's why he's hid it from me, he claims it wasn't a random girl it was a celeb model. He always breathes down my back about what I get up to and what's on my phone and then he is the one up to all the mischief. I just don't know what to do now I don't want this to be one of those other arguments we have where I run back to him and forgive him he drew the line he's literally punctured a hole in my heart and lost my trust. (we have been dating for 2 years)