Hi. Many girls like you face the same problem globally. You have to understand one thing. That is trusting a male doesn't mean since u trust u can allow someone to touch you. In your case of Ur cousin Brother at the young age when u didnt know anything he touched you and finally u quit him. Now u r trying to quit this person also. Nobody has the right to blackmail girls. Go and talk to him clearly till he understands. You can decide on wat is good and bad. Noone can cheat you. For some months try to develop urself rather than feeling loss of trust and abusiveness. Make your mind strong. You can talk and explain to counsellor so that they will help u to come out of this issue.
Next Steps
take 1 or 2 sessions of counselling. u will clear and confident.
Health Tips
dont develop trust easily and dont worry that u can't trust anyone. instead trust urself with confidence.