Relationships

Am I an idiot, or is there a reason for my concern?

We have been together for five years, and until about four months ago, everything was okay. Here's a little back story; I was a whore in my younger days and never really cared if they stayed or not, but with this woman, I felt something I never felt before from the gate. I told her about my past because I wanted her to know everything upfront, so if someone were to say that I used to be this way, not to trust me, she would already know. Well, it didn't work out as planned; for one, my ex tried telling her that I was still sleeping with her, which I wasn't, and there were a couple of times where it looked like I may have, but I showed her there was nothing to it. Yes, I was able to prove it. Anyway, about four months ago, I think she cheated. I kept catching her with 2nd line and dating apps in the not installed library, however without her knowing, I could get into her app store and remove those apps from the not installed library, and when I checked later, they were back in there. She claims she didn't do it; well, the only way they get there is by downloading and uninstalling them, I told her this, and she says, well, I didn't do it. Well, I know that is a lie, so I believe she cheated on me again after telling me she didn't want to lose me and would do anything to make sure we stayed together. What do you think?
Am I an idiot, or is there a reason for my concern?
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