Girlfriend critical and gossiping behind my back

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.

You can spy some more if she is using google account. Go to myactivity.google.com and you will see everything she sees when she was using her chrome browser, or android phone apps. Even FB hidden private groups and such. Its all there.

Nowadays its rule of thump - everything you see google see as well.

Well

As in any problem in relationships you can only Adress this together

1 you may be a fool for not noticing what is wrong
2 she is a dick for talking rude about you behind your back
3 also if she has a problem she should Adress it so that you can find ways to change it

I’d use the constructive route

I will start off by saying this.... You shouldn't be snooping on her. I think you already know that is wrong, though. I'll also say this.... you shouldn't have to feel like you HAVE TO snoop on her. I'd venture to guess that you wouldn't be snooping on her if there weren't reasons you felt like you had to in order to find out the truth. I don't necessarily think you should hold it against her for dating/sleeping with another guy while you two were early into dating. Well... unless you'd already had the exclusive talk, but I would assume you hadn't if you were "very early dating" as you put it. So, at that point there really was no reason to assume she was not free to date other guys as well. Think of it this way. She was dating him... even slept with him... but now she's with you, NOT him. So, obviously she went somewhat far with him and yet still decided you were more her match. If that was a problem for you, though, I could understand. But that would have been something to deal with then. You shouldn't be holding that against her now.

All that said....

I cannot necessarily tell you what to do, but I can certainly tell you what I would do if I were you. And, me personally, that would be an INSTANT deal breaker. Trust is not easy with me because I've had so few people worthy of trust. Respect is also VERY important to me. Her bad-mouthing you behind your back and/or allowing friends to bad-mouth you unchecked is NOT okay. It shows a complete lack of respect. Even worse because she says these things behind your back rather than having the decency to talk to you about it.

MAYBE there are some things you've done wrong/could have done better. Hell, if that is the case it would be great if you knew that so you could work to improve it. ...BUT, the moment she talks behind your back rather than just discussing them with you her argument loses all validity. Maybe you could talk to her about it in hopes of improving things, both from your side and from hers. If you wish to do so in hopes of saving the relationship then I wish you the best of luck in that.

Me personally, I would not be able to look past that. That would tell me she is not the right woman for me. You deserve somebody who can treat you with the love and respect you deserve. Who can appreciate you even despite your flaws. Who can help you to become an even better person rather than just disrespecting you like this. Maybe that still could be her, I don't know... but if not then you deserve a chance to find the right woman. Good luck to you.