Help with understanding toxic partner

Hey everyone I just wanted some insight on a situation with my ex, he would get mad if I walked the wrong way , he would say I do dumb shit outside but I’m walking regular or maybe awkwardly because I know he is watching my every move literally sometimes he would walk behind me and I would look back and he would get annoyed , usually everything would annoy him with me , certain awkward movements I do behind him being aggressive. I never understood why none of my ex bfs did that. I tell him I can’t deal with him And he doesn’t admit to it and says he doesn’t know how I graduate and I just feel overwhelmed and nervous all the time behind the past. Idk why he treated me like that , or why he continues with that behavior. I can tell he likes to bully people but to the right people and let others walk alll over him and rob money from him.