First breakup, M19 (me) and F(18) after 2 years. Hopes of her coming back and no peace with myself as time goes on.

Hello everyone. I will keep my story brief not to waste time. I was 16, she was 15. It was both of ours first relationship. We dated for a few months, but I threw it away because of my pride of dating a “dream girl”, when she didn’t live up to this expectation. Fast forward, 6 months later, she never really moved on. My friend said she really likes me, maybe it’s worth a shot.
We dated for 2 years. In the first year, I was still an asshole at times, by not being all in for her with my actions, she was obsessed with me. We spent a lot of time at my home during quarantine. But then, in the second year, it changed. As we dated for a year, I started to feel safe and happy around her, even if she wasn’t this previous idea of a “perfect” standard girl, based on my teenage idea.
However, she slowly started to shift. I had incidents where she’d dance very closely and text one guy the next day at my birthday party, or someone was clearly grabbing her ass while dancing with her but she kept dancing since he “stopped”. I forgave he. She wouldn’t try to change for me as much as she did before, but I didn’t care, I liked her the way she is. In winter, she told me she doesn’t know what will happen during university, and that she feels like she will miss out on being single in college, not even being able to talk to any other guy. She’d sometimes tell me how after knowing she got me (her perfect crush),it doesn’t feel as exciting, or that she wishes we met later in life so we wouldn’t have this thing of “never have experienced anything else”.
Now, we broke up. She first broke up when I could tell she wasn’t planning long distance and I was getting too needy while she became more focused on herself. She said the spark wasn’t there anymore, and she wasn’t sure already but she came back a day later. Told me she thought we would end it by the end of summer, which was shocking to me, I had no knowledge of this all along. She left we broke up again. Weeks later when I visited, she told me she kissed two other guys at a club and had tinder ( I found out by accident). She also followed some thirst trap celebrity on Instagram. I still was desperate and spent time with her, had sex, cuddled. She visited my country once again and this time I was cautious but still opened up and we kissed.
Fast forward a month of no contact at all, she texted me she’s very sorry for how she treated me. We opened up, I can see she still misses me and we both admit we feel safe and so good talking to each other. But her head is confusing and she doesn’t know what she wants in life. I don’t know if I could forgive her for all of this anyway, and I don’t know what amount of work she would have to do to get my trust back ever again. I tried to seek revenge by working on myself, I tried to say how this person doesn’t deserve me so why am I bothered. Sometimes it helped with my severe depression, but still,3 months post breakup I can’t sleep or be happy most of the day. Only now talking to her makes me feel so safe again. I’m also very jealous of her life abroad.
My only questions are, what the hell do I do about any of this? And do I still keep in touch with her at all? I’m losing my mind and even though she wasn’t perfect in many things for me, she was perfect to me, I can’t imagine her being that version for someone else or it hurts me seeing her so good but without me there. It feels like the more time passes the more I hurt, I know she hurts and cries too.