Let's say I go through her phone and there's nothing sexual? What is unacceptable? Old pictures with ex's? Texts with ex's? I can't put a finger on what she thinks I'll blow up over if it isn't sexually related.
Only you can determine that...there is no code written saying this is acceptable and this is not. Again, like i said only good could come out after you go through things together.
You go through her phone, nothing sexually inappropriate with an ex but she is still conversing with her ex. Is that acceptable in your relationship? Is it ok for you to keep in touch with ex's? It sounds like you have not laid those ground rules down with each other. If you have you would not be asking these "what is right and what is wrong" stuff.