Vent about my most recent ex

(First of all, I apologize for the grammar mistakes. As it says on my profile, English is not my main language)

These past few days I've been offline bc i've feeling pretty bad tbh. Basically, my gf (actual ex) asked me for the passwords to my social media accounts. Of course, I found this to be quite invasive and politely refused, saying that I didn't feel comfortable doing so. That if she was insecure about something on her mind, we could talk about it and resolve it in a healthy way which is something I always chose to do when I was insecure. (After all, there's no point in fighting because of anxiety paranoia that I get out of nowhere.) Believe me, refuse to give her my passwords was enough to trigger a domino effect that made her call bad things, put her finger on my insecurities, gaslight me and stop talking to me for two days in a row. When she returned, she tried to blackmail me by saying "it's just an account. If you have nothing to hide, there's no reason not to share it", and I refused again. We had a more severe fight and in middle of this, I said she was being manipulative. And believe it or not, I was the one who came out on the wrong side of the story. She said that I deserve to get screwed over a lot in future relationships, that everything between us was over because of MY fault. That I deserved all the suffering I've been through and blah blah blah.
And today, 1 week after the breakup, I discovered that she keeps gifts from her ex in her closet (something she had sworn to me she had thrown away), and told her friends that she always missed him. Man, I felt used. But she swears that I'm the one in the wrong for not sharing the passwords.
Honestly, I'm really upset about all this, because I was really liking her.

Besides, now that everything is over, it's funny to stop and think that she was never wrong in our arguments. I was always the one who had to apologize even during the times (like this one) when I was sure I didn't do anything wrong. Fucking hypocrite.