[FULL] My teenager sister thinks my boyfriend is using me to get to her, and mom's on her side

Little sister thinks my boyfriend is a child predator who is using me to get to her, and my mom is on her side. I, 19 male, have been dating my boyfriend, 20 male, for 6 months now. I currently live at home with my mom, 50, female, and my sister, 15 female while I attend a local college. My boyfriend obviously is not straight, me as well. My mom was supportive when I came out, and my sister was too. When I started dating my boyfriend Kev, my sister got a little obsessed with him. It just seemed like a weird teenage sister thing at the time, but it turns out, according to my mom, that she actually has a crush on him. That's weird, but again, a little sister thing. It's not going anywhere. I've told Kev about it, and he thinks it's a little uncomfortable, but he can deal with it. If she kept it to herself, I wouldn't mind it. But she doesn't. She constantly wants to hang out with us whenever he's over, never giving us a moment of peace. Last time Kev was here, we were in my room, and she walked in on us making out without knocking, by the way, and huffed before slamming the door. After he left a few hours later, she came into my room again to talk to me. She proceeded to tell me, to my absolute shock, that Kev was straight and I was abusing him by not letting him leave me. I didn't even know what to say, so I just asked her what made her think he wasn't. She said he was obviously into her instead and was using me to see her. I completely lost it. Months of borderline harassment towards my boyfriend, and that's why. I told her that her creeping on him and making him feel uncomfortable didn't count as interest, and that she was a horrible person and an awful sister. I told her to stay away from my boyfriend, and if she ever brings him up again, don't be surprised when the back of my hand meets her face. She started crying and ran off into her room, but I don't care. I'm tired of having to act like she never does anything wrong. She essentially called my boyfriend a pedophile and accused me of abuse. I'm fed up with it. And my mom said Kev isn't allowed back at our place until I apologize to my sister. I said, good, I don't want my creepy sister around him and we can just hang out at his apartment anyway. I'm spending pretty much all my time at school in his place. As time passes, though, I keep wondering if I overreacted. She's 15, but it's still disgusting. I just couldn't take it anymore. Hey, it's me. I realized I forgot to add some needed info. I wasn't thinking about it at the time. Firstly, my sister forcibly entered my room. I locked my door and she jimmied it open. She does it all the time, so I forgot to mention it. Secondly, for those confused as to why my mom isn't helping, it has been like this my entire life. My mom doesn't care about me, at least not nearly as much as my sister. Basically, 15 years ago, the doctors told my mom that there was like a 5% chance or something that she would be born healthy and alive. When she told my dad this, he left her and I haven't seen him since. Good riddance either way. But the point is, my sister is her miracle baby. She's the golden child of the family and she can do whatever she wants with impunity because she almost wasn't born. She's also the straight A varsity cheerleader. She gets everything she wants, literally. I don't have anything of my own other than my room, which is half the size of hers, my phone, and my boyfriend. And she keeps trying to take all three. She thinks she can have my boyfriend because she has everything else I do and is jealous that there's one thing, just one thing, that is not hers. It's so infuriating and dehumanizing. I've been talking to Kev and we've been thinking of moving in together, at least until we finish school. We've both gotten into the same four-year school, so it'll be good there too. The more I thought about it, the more I blame my mom. She took all my prospects away and gave them to my sister. It's cartoonishly neglectful. I spent my whole life feeling like an afterthought, and now there's someone in my life that cares about me so much and it just feels amazing. Of course she'd want to take him away from me. Sorry, I forgot to mention all this. I was just furious. I'll be going no contact as soon as I can with both of them. Thank you all. Final update due to the final nail in the goddamn coffin. When my sister was 12, my mom got her a dog, a little beagle puppy named Baxter. About a month into having Baxter, my sister decided she was bored of him and unofficially gave him to me. Since then, I've been feeding him, walking him, and paying for his training which, if you've ever had a beagle, you know is not easy. Everyone in the house agrees Baxter is my dog. They refer to him as my dog. They tell me, get your dog away from me and let your stupid dog in, stuff like that. He absolutely loves me and I love him. Last night, my mom called me into the living room where she and my sister were and told me that if I didn't apologize, she'd take my keys to the junky car that I paid for so I couldn't see Kev or go to finals. And she'd put Baxter, the dog I completely care for and who only responds to me, in the kennel. I told her she had no right to do either of those things. She said to get over myself and just apologize and as long as you're under my roof, I can do what I want. I still refused and just went up to my room and packed. After both of them had gone to sleep, I took Baxter and all my belongings and went to Kev's. He'd always told me that if things got rough, I could come to his place, day or night, rain or shine. I always planned to take Baxter with me when I moved out anyway, so we had already put in a request with management for a pet. We'll just keep him a secret until it gets approved. This morning I woke up to like four missed calls and several texts from my mom that amounted to, Where are you? Where's the dog? Are you still picking your sister up from cheer? What the hell have you done? I told her that I'd be back in a few days to move any furniture I needed out and she could sell the rest. She told me to bring my sister's dog back and I told her to screw off. My sister doesn't care about Baxter and never has. He'd probably starve to his grave if I left him there. She told me she's junking all the furniture and I'm not permitted in the house anymore. Whatever. I'm officially moving in with Kev. It'll probably come back to bite me soon, but I just don't care. Being homeless would be better than being there. I don't know where my life's gonna go, but for right now I'm happy. Thank you to everyone who's been nice to me.