AIO

My boyfriend and I (both 25) have been together for 3 years. Recently I went through his phone and saw instagram DMs exchanged between him and another girl. The most recent message was from 2024 and the others were from 2020 (before he and I knew each other). The messages from 2020 were of him responding to her stories with heart eyes calling her his wife. The dm from 2024 was of him responded to her story saying he loves her vlogs. I confronted him about this and his response was “we were probably going through something at the time”. Please tell me if I’m overreacting for being angry with him and considering that micro cheating. He definitely crossed a boundary that I’m not ok with.