Is there a way to prove my ex was in my account? Or evidence that she was or still is hacked in my iPhone?

Hi I have an iPhone 5se. One day I was in my gerrage working on a cabinet and my girlfriend walks out of the house holding my fon saying I’m busted! I left my p on the kitchen counter and she got it and somehow figured out my 6 digit code and read all my text all my messages emails everything! And ever sence I notice changes on my phone like emails opened, and security code requests. Is there a way to find out if she still in there or has access and can I prove it’s her?