Violation Of Privacy

I have been in a relationship with my wife for (3) years now... On several instance my wife has displayed a lack of trust and insecurity during this time... Everything is all good when we are around each other 24-7 she is the most secure, confident women on the planet.... The moment I divert some attention to some of my other priorities besides her (ie. running a small businesses and other hobbies like video games) she becomes insecure... and starts going through my cellphone and checking behind me to see if I'm cheating on her... I never in the three years of our relationship have gone through her phone and checked behind her cause I have trust in her... Also I am a firm believer that a person will do what they want regargless if you watch them and investigate them.... A few years ago one of my female cleints of the office send me a message in the DAYTIME.. to call her back regarding WORK.. My wife saw it and I was cheating with her... She used to check the history of the last websites that I visited just so she can see who I was talking to on Myspace..... and now So this past weekend I happened to leave my phone in her car and she goes through my phone and reads all my text messages that were SENT to me ....One of the messages happened to be from and old Friend from HIGH SCHOOL... who is also MARRIED... AND LIVES 700 miles away the message read as follows" I see your not calling me back.. I miss you" my wife goes crazy and says I'm cheating and all kinds of stuff.. And why did I get married if I still wanna pay the field... I'm confused I didnt do or say I missed anyone further more.. and the text wasnt meant in a romantic manner I know that for a fact... This incident was jus a carry over of events prior so I feel more violated that she is always going thru my phone...I feel she just doesnt trust me flat out.. SO am I wrong for not answering questions concerning the text when anything I say will be considered an excuse....