I happened to see a message on my girlfriends phone which was critical of me from her friend. There are no pass locks and curiosity got the better of me so I read some messages. My girlfriend has been ill, but didn't make me aware of how ill she had been, and I read a series of messages which said things along the lines of 'for an intelligent guy he's thick as ****' (friend). My girlfriend agreeing. Then 'oh he's started looking after me now (girlfriend) and then' it's a miracle!. I've seen other stuff on her phone before about 8 months ago where they were criticising what my daughter was wearing in a picture when she had been dressed by my ex wife. (flashed up when I was using her phone with her permission) Yes I shouldn't have looked at her phone this last time but I already have issues trusting her due to her seeing and sleeping with someone else when we were very early dating. Other messages talked about my self esteem and her friend called me 'mental' and a 'fruitloop'. Is this a huge red flag or am I overreacting. I don't criticise and mock her to my friends so I don't really appreciate it back.