Emotional and financial abuse tw

My boyfriend over this whole month as ‘fines’ for his bad behavior leading to my reactions,example him out doing ketamine and cocaine and balloons with his friends all night while he told me he was working and I brought it up with his brother there and he made me pay €300 or he wouldn’t speak to me,he also made me pay €300 for him to stay after we had an argument and now again €350 for “being disrespectful” because I will say Yes,but or No when he thinks the answer is a yes.He made me repeat this long sentence ten times today and because I didnt want to thats why I mainly “disrespected” him.(I ended up having to say it anyway) We are together almost 3 years and I really dont have anyone else (no close friends and not close with family) I feel so trapped and literally like a slave or a monkey in the zoo and for some reason I still love him.I only feel safe when I am with him but I genuinely am getting self harm itches again really bad and I know people are just going to tell me to leave but I really can’t.Im spending every day the most depressed Ive ever been and then super happy with him but I dont want to reach out for help because I know what everyone will say and I simply cannot leave.What should I do? I dont know why Im doing this to myself