Caught boyfriend reading my texts

Here's the story, this morning I woke up to find I had two new texts that had already been read. My boyfriend has got out of bed and was sleeping on the couch. So I knew something was up, I asked him, he said "why would I do that" and then avoided me. Finally I decided to straight up ask, did you read them or not, and he said yes, he had. 
Now we've had some trust issues and issues with phones in the past, mostly me and what he's doing and talking to. But I have never once even tried to read his texts and phone that he keeps super secretive. He has his vibrates even off. 
Anyway, I have absolutely nothing to hide on my phone, I'm more open about it then he, and I feel like iv been violated, and I don't know what to do. 
Any advise on how to deal with this?