So I'm 16 and been with my 19 year old boyfriend for nearly a year now and he's always had some secrecy about him but recently he had been getting notifications and not viewing them till I was far from him. That night I checked his phone (never did before) because I knew he was hiding something. I found messages with him flirting with another girl? I confronted him and he said it was just that one day. I later talked to the girl who also said the same thing. I let him off and he broke down and said it wouldn't happen again. But yesterday he was being secretive again and when I went to look at his phone he had changed the passcode and will do his best to keep his phone out o my way. Should I be suspisious? Or am I over reacting?