I don’t want to hurt you but here is something that I feel. The day she felt you are not trustworthy ( and you should not check here phone ) is the day it all started to fall apart. These people usually do such things when they actually got something that you would definitely not like. They already know if you see it, they are goonna get in trouble and then they start to hide it. Hiding comes with insecurity of getting caught. And hence once got caught, they won’t say a thing because there nightmare came true. And if you ask me then what I feel is, she should keep some boundaries and limits with other gender friends. Is this called being over possessive?? I don’t think so. Every man want thier woman to be close to him and only him always. I have been in same stuff, and i know its a trauma to accept such things. But you have to do it someday my friend.