Basically that. He gave a flimsy excuse why he was on my phone and 'accidentally' stumbled on my messages and 'accidentally' read a message from a guy. The guy is gay, and is a mutual friend.
This happened a few days ago, and while i'm not as angry i'm still mad. We don't go on each other phones. He wouldn't even allow me to borrow one of his phones (work/person) as we were taking two cars on a trip and my phone had died. If I had ever seen him on my phone it would have made this story a little believable that he had accidentally ended on my FB messages. In my previous relationship we both had each other thumbs on each phone early on but that was incase one of us wanted to google/call and our phone wasn't to hand.
I can't seem to get over it. I want to hide all my journals/change my passwords/put one of those apps to see if someone is snooping. I really hate this feeling of resentment.