Is this a red flag?

I’m processing through my trauma to learn from the past. My now ex would go through my phone and laptop like emails, notes, and browsing history from years prior. I’m talking stuff from 2015. He’d stay up most of the night after I went to bed to do so. When I’d wake up sometimes he’d be like who did you send this pic to and it was taken back in 2013. I’ll be posting more threads but since I’m new to the whole red flag thing, I want to make sure I can spot them, learn from it, and not repeat