My ex came back second time and I don‘t understand what‘s wrong with her

I have to write this fast because it‘s important and I am at work so basically my ex and me broke up like twice and now she contacted my mother because of some bs and she wanted to also contact me (I blocked everywhere) . Long story short I said ok i don’t care come back and now she tried to gaslight me into bringing the good memories and she is literally the SAME person as before. The no contact did literally nothing to her. Still so bitchy, disrespectful, immature. She said that she was texting with many guys but none of them were like me and that she is hooked on me and she can’t let me go. I don’t care about her because she changed me basically. I don’t know what to do but I know i have to leave her somehow