Am I being selfish?

My mum & stepfather we’re together for 17 years.. they met when I was 7 years old and had a baby straight away. When I was 12 years old he started touching me in my sleep.. when it first happened I was scared shitless to tell my mother cos she always threatened to send me to live with my dad. So I didn’t say anything.. also as I would wake up to it I was confused and thought perhaps I’m dreaming this? It stopped for a while (unless I didn’t wake up to others) and I woke up to it again by the time I was 20 years old. By this stage they had 3 children together & I knew saying something my mum could possibly divorce him & I was trying to think of the children.. also my mum always accused me of trying to divorce them so I thought she might think I’m lying.. anyways he broke up with her months ago & there was lots of speculations that he and his half sister were being appropriate and I was just so over it so I spilled it to her what he did to me.. she believed me and was very apologetic and upset etc ..

Anyways today we were eating and then she was meant to drop the kids off to him.. anyways he ends up coming to the restaurant and I said to her as if you make him come here I don’t want to see him? And she told me shut the fuck up I don’t care and then when the kids left I had an argument with her and was telling her ok you didn’t know he was going to show up but you could of said sorry not tell me to get over it and shut up and she just kept going on saying how he’s her kids father ? Also when he came she was like smiling so much at him ok I u derstand she still loves him but how could u smile and be kind to someone who’s done that to ur daughter? I explained all of this to her and she was just saying g I don’t care I don’t need to suffer my whole life .. I told her it’s not fair I have to deal with all of that pain and he just gets to live his life ? And she just showed no sympathy towards me like as if she’s over it ??

I’m sorry I wrote a lot but I dont even have my own mother to protect me and she treats it like a joke I didn’t even report the bastard to police cos I didn’t want to upset the kids but I’m so upset