I just broke up with my ex tonight and I can’t get over the feeling I get from this.

Basically, he has a sister who is 5 years younger than him (he’s 28) and I’m actually his sister’s age. Sister has a best friend and he started bringing her around. From literally the day I met her, she made problems. Lied to my boyfriend and said I was talking about her (apparently? 🤷🏼‍♀️) deep mental health issues, that I was smoking weed in front of her (I’ve told my boyfriend I don’t and don’t like to), and trying to purposely exclude her. When it first happened, he went off on me and said he didn’t believe anything I tried to say. Afterwards, she gave me an apology (obviously bullshit) and I thought we were fine. She would gossip about her life, his sister, etc. She ended up telling me that he told her about going off on me. She also told me that her and his sister liked to make fun of him and how she basically hated my ex, like to the extent she “wanted to punch him in the face”. I just kind of ignored it because I felt like I couldn’t say anything to him. Then she turned around and made even more lies about me, like that I was cheating. Bad enough that my boyfriend screamed at me because he believed her. I just cut contact with her and tried to move on. Other friends in the group told me she was still gossiping but I just ignored it. Then my ex texts me tonight and is like “xxx is saying that you talked to this other guy? Why?” Literally ALL I texted him was “Lame you didn’t tell me you went back” (he went back to a job we both quit). That was literally ALL the conversation. My ex tells me that he overheard her gossiping with someone else. I tried to defend myself and said “Yeah well she’s ALSO told ME that she stalks your social medias to make fun of you. Clearly just likes to talk shit and make problems”. He said “Get your drama out of my face” and said that I should have talked to him about my text instead of him hearing about it. But like ??? It was a simple text? It’s not that serious? Why do I have to tell him something like that?

I ended it bc I got tired of feeling like I have to walk on eggshells while she literally can talk shit about him and he doesn’t care. Like I tell him something she ACTUALLY does and he blows it off. But he hears something I do that’s a LIE and I get the 3rd degree?