Is she being a bitch (long story)

I've recently had a huge fight w/ my family. My parents are divorced since I was 1 & my dad is married to my step mom since I was 2 years old. I've known her my whole life. She's always been good to me, I wouldn't say like a mom but like a friend. We never ever had any type of problem. I was raised w/ my mom & she met my step dad when I was 6. I'm 19 now but when I was 15, my dad that was never there for me was trying really hard to get me to see him as a friend. Which was and it is still hard since he was never there for me when I was a kid. Anyway, so when I was 15 he told me that him & my step mom go to those swingers houses. Parties that couples have sex with each other/exchanging partners. So all of his friends that I've known my whole life & been to their houses were part of this. I was socked at the time bc I was so young that was TMI for me. He told me not to never tell anyone and my step mom could never know I know about this 'secret'. The same night I cried a lot to my sleep bc I was confused & the image of my dad & step mom doing that wasn't nice. I kept his secret w/ me as he told me to, even though every single time I'd visit him he would tell me about these stories & how they share each other. Would make me want to puke but I never told him to stop bc I felt bad. Pity for him. Anyway, when I was 18 I was going out w/ some older guys, I was single and just living my life. I didn't tell my family bc I don't think it's appropriate & I'm NOT my dad. When I was spending some time at my dad's house, he went through my stuff/cell phone etc without my consent & found some texts between me & the guys. I wasn't fucking 100 guys it was literally 2 guys but they were older & he got furious. He sent their phone numbers to my step mom so she could do some research on them & one time when I was going out w/ one of them to a bar they followed us and made a scene in front of everyone. My dad grabbed my arm and hurt me telling me to leave and that he's my father and all that crap. He almost fought the guy, it was terrible. After that my step mom kept messaging me telling me how much of a slut I am & that I always made it look like i was a saint an angel but I was a lie & that I'm heartless I don't care for anyone just myself she called me a prostitute asking how much I'm charging the guys & I couldn't believe it. I couldn't just listen to all she was saying & not bring up what she does in 4 walls w/ her friends so I did it. I said you have no right to say SHIT about me bc if I'm a slut you're 10x worse, I know what you've been doing w/ your husband's friends. (I don't have anything against ppl who's into this, but sitting there listening to her calling me names while what she does is worse I just couldn't bear). So later that day my dad came up to my grandparents house where I was & called me names saying he trusted me w/ his nasty secret when I was 15 & that I ruined everything for telling her that. He made me feel terrible when his wife was doing the same. Plus my grandparents were defending him, so I got up left & now I'm living in a hotel room. Story of my life.