Boyfriend is best friends with a slutty girl

I started dating this guy I went to high school with 6 weeks ago, I'll call him Tyler. He is best friends with a girl who we will call Maddie who not only dresses slutty but who hates me. Is it ever appropriate to be friends with a female who hates your girlfriend? She hates me because of shit that I did in Junior High and High School. And it wasn't just me it was everyone. She was 11 in the 6th grade with size D tits so we all called her a slut. I'll admit I was a bitch but who wasn't. I wasn't so nice to my boyfriend in school either. I was mean, like everyone. You would think if you're being called a slut you would want to prove people wrong. People called her a slut all throughout high school and senior year, she literally decided to be a slut and came to school in a short skirt and tank top. She was 18 then so Ig it's not that big of a deal, but everyone is calling you a slut so your senior year you decide to be a slut. Tyler came more out of his shell that year too and that's when I stopped being mean and started liking him.

We are in our 20's now and Maddie has no shame. She talks about sex. Dresses slutty and bangs guys and chicks She's an absolute whore and he is friends with her! When I bring it up to him he says they've been friends for 14 years and when he was crying from being bullied she was the one wiping his tears and building him up. In HIGH SCHOOL! This isn't High school anymore. I don't think Maddie is a bad person she's just a whore and I hate her. She's fake nice to me. She acts all nice and respectful but I know she hates me. Maddie became what we said she was and he still wants to be friends with her. His excuse is her sex life is none of his business. True and not true. My mom isn't on my side because I was always in the office for bullying. She thinks Maddie isn't a slut she's just not ashamed or afraid to show her sexuality anymore. My mom was bullied in school so she's biased. I just don't like my bf being friends with her.

I wasn't the only one who bullied my boyfriend and I wasn't the only one who bullied Maddie. He was weird, he would cry in band because the noise was too loud and everyone called her a slut not just me. Also why would Inbe jealous of someone who was called a slut and life was miserable through school. I would never want her life.