Was it my fault the relationship ended, or is she just insecure

This is about a short-term relationship. I'm someone who tries to take accountability. I'm unusure whether this was destined to fail due to her insecurity or my poor decision. I feel a bit guilty and am not sure how to view this and would like some suggestions whether I just dated someone toxic, or I made a poor decision.

I met a girl online, great first date, and by the first she had already told me that she had removed everyone on her dating app apart from me. Which I liked but, but looking back it felt like a red-flag, I've had 2 girlfriends and some few talking stages and most of them take time before that. By the third date, she is already saying how when she posts photos of herself she just wants my attention and mine only. I thought it was cute but in hindsight, things where moving quite quickly, but as a man I see it as, if she opens the door, I just walk through them. Now after she had told me about her past, dad leaving for days, getting very angry and throwing tantrums and she had been cheated on, and hadn't dated in 3 years, that fear of abandonment thing made sense.

We had 5 great dates and by then I was getting all dreamy. However in between our 5th and 6th date, I had an assignment due and I couldn't respond for 4 hours. I checked my phone and she had tried to re-follow me which was weird, because we had followed each-other already. it turns out she thought I was ignoring her, got annoyed and blocked my threads account, which blocked all my Instagram accounts. This was a huge sign of instability for me. A confident girl wouldn't go straight to that kind of impulsive state. I told her not to do it again, and empathized with her as i understood it. She had told me she felt like she doesn't deserve this, and is used to chaos. I told asked if she'd feel more comfortable if i told her we're exclusive and she got excited.

I let that go, we had another great date. During this whole time another weird thing was she agreed with literally everything I said. Which was nice, considering the last person i dated (my ex) was very disagreeable, but it did feel a bit weird. Regardless this girl made me feel amazing, as if i was the best thing in the world. Anyway, i have a podcast which discuss some of my own traumas and how I have been with other women, she got insecure over it. We communicated and moved forward. However after a great next date, she started getting all weird, removed the posts she had put up of us and wanted space. A day later she wanted me back and apologized. Now i started feeling very weird. To this point i treated this girl like an absolute angel, reassuring her at every point.

She then sent me a screenshot, of a comment I left on my teammates Instagram saying Beast, I'm a powerlifter, and so was this girl teammate. Absolutely nothing flirty. I knew her boyfriend very well too. this started to annoy me now. I reassured her and was nice and said I only had eyes for her but kept getting accused that I'm giving attention to other girls and arguing about it, saying i'm not listening. I'm not, at least not in that way. Now my big mistake was this, we went on one more date and I think I just felt insecure about the whole situation, and I made a poor decision and followed another girl. I didn't message, like any photos or anything, I had 0 intention to at all, but in saying so I guess I had lost a lot of confidence in myself. I felt like I had treated this girl very well, and my best wasn't enough. It felt like she needed a insatiable amount of reassurance.

She clocked onto it within 4 hours (clearly stalks my account), removed all our posts again, unfollowed me, and started putting on her story 'hungry dogs are never loyal' as if she was indirectly trying to put me down, didn't communicate. I didn't cheat. It was disrespectful at the most. This was the beginning of the end. I unfollowed the girl as soon as I saw it as i thought it might be related to that. She accused me of disrespecting her, and basically ended things from there and said i was unstable and unsafe. I apologized as much as possible, but she was having none of that. I promised I'd never do it again but that was it. I never got a chance to make up for it. I probably over-apologized to be honest, I wasn't very calm in that situation.

I'm not sure if this is something i should feel an immense amount of guilt, or that she was just someone looking for problems. You attract what you fear. Lesson learnt obviously but i feel like a healthy girl would at least say 'hey it made me uncomfortable that you're following girls' and that would be it.