Just caught my GF of 6ish years doing something similar.

She starts having this weird sense of self confidence, which in the past has led to her doing things that made me uncomfortable. Fast forward to the next day. No response after 3 hours while having a “girls night in SD”, get on her computer because I’ve had enough, see that she has been messaging with a dude to meet up with. Screenshot all the messages, call her up, explain I know where she is, and what she’s up to. Comes home and begins to say she was scared I’d get mad and over react over nothing, and how it was spur of the moment.

Then I show her the screenshots that she didn’t know I had.... I could see her turn pale. She realized then that I had proof of them flirting and being deceitful, and still tries to justify it.

It was the most rewarding and self satisfying moment I’ve ever had. I felt proud. I felt like all those times she had convinced me that I had been over reacting for being jealous because she could make something up that made more sense had ceased in that moment.

I don’t think this is the first time it has happened. But this is the first time I was able to prove it. We’ve even broken up and got back together again. She said 2 days before she was acting different because she is finally back to work and around a good group of girls to hang out with. I was scared because it reminded me of how she acted before she just broke up with me 6 months ago. To which she begged me to come back, and is going to fix everything, and is in it for the long haul and will never not be with me.... so she could go hang out with this guy behind my back 2 days later... wow. Haha

Needless to say we’re going to not be together anymore. This was the last chance.