I (20M) and my girlfriend (19F)

Throwaway as my girlfriend knows my main. Long read ahead, so I appreciate you taking out the time to give this a read, kindly don't be judgemental, if you want to say something along the lines of, it's just teenage drama, you're being insecure, just end it, you're karma farming, you're looking for attention kindly refrain from commenting. I genuinely want real advice and perspective. Thank you in advance!

Me and girlfriend have been dating for 8 months, she's the most perfect, loving, caring, empathetic understanding girl ever, we're each other's first serious relationship. I had one girlfriend before her and she had one boyfriend before me. I had never sexted, been intimate, kissed, hugged or even held hands with anyone. Me and my ex just used to say I love you to each other and never did anything more but it ended in in a grand total of 8 days, I've told my current girlfriend each and everything in the beginning only, I've left no detail out.

She has also been transparent with me for the most part, she'd told me that she had this 'friend' that she liked but he was only that a friend, a couple of months later we were talking about not being over exes and stuff (I wasn't over my ex and I clearly told her that) but she told me that she missed him and cried for him whilst we were together and she loved him (he left her only 2 months before me started dating, I didn't know about the timeline), things got kinda bad she told me she clicked a one on one picture with a guy that likes her and I found it very disrespectful, I ended the relationship but she pleaded and we got back together. This was 2 months ago.

Today she tells me she used to sext her ex (she used to tell me that they barely even talked and e never called). Me being the naive fool I am had thought that she hadn't done anything with him. So It was a shocker for me and now I'm contemplating what should I do? Both my previous and her previous relationships were long distance, our current relationship is long distance too but we've met and kissed and done almost everything except sex, I feel betrayed and at a loss of agency as if I knew that she used to sext her ex I would'nt have dated her, it's not about why she did it it's about being honest and transparent with your partner. I just want a partner who has a similar experience as me in these things.

She's broken my trust a few times before (no infidelity just breaking the boundaries that we'd set), the relationship is amazing for the most part but these breaches of trust are worrying. I'm obviously not a perfect person in fact I'm far from perfect but throughout the entirety of our relationship she has never had to worry about any other girls as I don't even have any female friends (that's my personal choice and she has nothing to do with it). But there have been instances when she has defended her friend's actions, one friend gave her a massage and she said he didn't mean any harm despite her being uncomfortable during the massage, other friend said he'd 'smash' her and she was like he's like that with every girl, another friend asked her to show him around the city (it is a date in my books, you can't tell me otherwise) but later stood her up twice and her reaction was he was there for her before me and she couldn't stop talking to her and it wasn't a crime to have guy friends (after the massage and smash incidents I'd told her that I could only stay with her if she cut off all her guy friend and she promised she would) but she was occasionally taking to this "he was there for me before you" guy. This was 4 months ago.

She has been genuinely remorseful throughout and cut off all guy friends after the 4 months ago incident.

We've started over twice, as in forgotten and forgiven all the past mistakes, conflicts etc. She's a very emotionally dependent person and I think it has to do with her being abandoned and cheated on by her ex and being abandoned by the "friend", so I don't want to hurt her but I've already looked past her mistakes a few times, so I don't know if I should/ could do it again.

Tldr: Conflicted about what to do, my girlfriend has broken my trust a few times and she's told me something about her past that was unbeknownst to me earlier.