My ex is taking unsolicited videos of me at school and posting them on Snapchat, making fun of my fashion sense. I hold multiple leadership positions, so I don’t want to stoop to his level. What do I do?

So, yeah, I’m a female, in high school, (16) and I have AP Biology with my MIDDLE SCHOOL/junior high ex-boyfriend. Him and I haven’t talked in a year, since I blocked him because he would not stop texting me after we broke up. He manipulated me, sexually assaulted me, and repeatedly used me for various things (money, food, transportation, etc.) He was my first ever serious relationship, and only one. I’ve discovered that I’m much happier single for the long term, and have no interest in boys or girls. And it sucked being with him. But, puppy love inevitably makes you stay together. Or passion. Or fear.

I would consider myself a relatively popular, successful person who attends my school-I have good grades, I’m in advanced choir, I take AP classes and I have a job- and I dress very uniquely, normally my outfits contain platform shoes, I’ve won awards for fashion, too. (I’m already a taller person, so platforms are simply just my choice. It makes me feel good and confident.) Between every class period, I typically get 2-3 compliments on my outfits or makeup from random people. I am extremely humble when accepting a compliment. I know that I am relatively attractive, but I refuse to be conceited. Nobody likes mean girls. In fact, I give to charities and promote mental health awareness religiously, I am known as the “mom friend” amongst people. I haven’t ever talked bad about my ex. However, some people started rumors that I was. They quickly died down and people really didn’t care. Despite all of the things he did to me, I still believe in respect, and karma. In class today, I was wearing a pair of platforms with a dress, and he takes an unsolicited video of me in my shoes and posts it to his Snapchat story saying “what the hell are these”. He later deletes it. I do bot have proof, but I’m pretty sure my friends do. My friends tell me what he did, and I am very confused and upset about this, and what I should do. He has a whole new girlfriend, which he’s been with for about a year now, yet he is posting videos of me, his ex. One time I remember him asking me to “dress normal” when we were dating. He also told me how I should do my makeup and my hair, and what I should and should not wear. If I did something wrong, he wouldn’t be very talkative to me. He also stalks me on Instagram, as well as his new girlfriend, too. I’m worried if he’s going to do more things that are hurtful and indecent. As someone who is on leadership teams in choir, I really have no desire to seek revenge. But I know I need to stick up for myself if I absolutely have to. I’m just really confused as to why. Why would someone do this? And what should I do about it? If at all, anything?