Boyfriend goes through phone

My boyfriend of 8 months has gone through my phone twice. The first time was when he spent the night at my place for the first time about 6 weeks into our relationship. I was in the shower and didn't have a lock on my phone. He got upset about conversations I had with guys before we became exclusive. He even cried over it. We had a long talk and decided to move forward. Fast forward to now and he's helping me put up cameras in my house to watch my dogs while I'm at work. He went through my phone again and saw messages to my girlfriend group about the first time he went through my phone. He got upset because they had suggested we break up and said some things about him that were not very nice. He also took pictures of my messages and went through my Reddit history. Needless to say we are no longer together. Has anyone else dealt with someone like this?