ex wont leave me alone.

So i dated this guy for about 2 years, we were each others first love. Our relationship was really good but it turned pretty shitty towards the end before i broke up with him. While we were together he was a clean, straight forward person. Immediately after we broke up he got into drugs & the "gang banging lifestyle". Ever since we broke up he constantly adds me on social media every couple of months. Hes been in a few relationships since & he still adds me to try and talk to me, while hes in that relationship. Also, i DO block him, but he has made probably 100 new accounts to reach out to me. Some are even under fake names to try and watch what i post.

What do i do??? Im so confused because when he tries to talk to me he's a complete asshole, so what is the point of him constantly trying to reach out?

(btw we have been broken up for over 3 years now. he's been doing this every 2-3 months for the last 3 years.)