I guess you have to ask yourself if you find something, then what? If you confront her with whatever you find, then what? If you find something that proves your anxieties are just, then what?
I’m not familiar with your entire story so I’ll just add this:
If you are looking for something tangible to move on from this relationship, that’s one thing. But if you have decided to stay with her, then you have to trust her.
For me, if there’s no trust, then there’s no relationship.