Four months ago she was at a out of town work conference. Our relationship was a bit rocky and we were arguing often during that time. This was before I discovered TRP. She finished up at the conference and wasn't replying to my text (we were texting throughout that day, and she always replies fast). 9:00pm came and I tried calling her (we usually talk on the phone at this time when she's away. No answer. For the first time in the past year she never answered the phone during our chat time. No reply to my text. 10:00pm comes and she calls me and says she was busy talking to work prospects.
Today I had her phone in hand and checked her FaceTime (video call) history. I saw a video call that was made that same night (four months ago) at 8:30pm for 20 minutes with a man who's name I don't recognize (I didn't get his number; his contact name was his email address). Ever since I've known her she has only used FaceTimed with her parents and me. My gut feeling was bothering me so much a few months ago on that night, and now there's maybe more evidence to support something was up.
What should I do now? Of course I can't confirm that she cheated. And I won't talk to her about it and show more weakness while divulging that I looked through her video call history. It would only put her on the defensive. Things are better between us now, but I'll feel like I'll never know if she cheated.