Not sure what to do at this point..

So my boyfriend keeps going through my phone while I'm sleeping.. and only when I'm sleeping. Before I go into details, let me tell you that he has always been the jealous type and a bit controlling. For example, I could be talking to another guy with no flirting, and he would go on my phone and block them. Or when I'm on my phone playing a game, he'll ask me every 5-10 minutes "what are you doing" or "who are you talking to?." Anyways, the first time he went on my phone while I was asleep, we had an argument about it. It was because when he first went through my phone, I felt as if he couldn't trust me.. even though I did nothing wrong. The second time he went through my phone, again while I was sleeping.. he found some messages he didn't like. I'm not going to lie, I fucked up and was flirting with another guy when I shouldn't have been. We talked things out, and we're still together. I'm not sure why, because if I was him.. I would've left me. Anyways, I understand that I hurt him and that I can't completely be trusted right now. I took the password off my phone because he said things shouldn't be like this. But he went through my phone again. I understand I messed up. But I don't understand why he feels the need to keep going through my phone. I feel like if I talk to him about it, he's gonna turn it around to be my fault like he always does.. even if it is mostly my fault.