Help? sex offender question?

When i was 15 i went out with a so called 20 year old he was really 28 but i didnt know. This was in the miley cyrus era im not saying its her fault. Well i told him to stop touching me and he didnt stop and he was so disgusting. But i went back to him a second time and he touched me again i told him no. I was afraid because he was getting rough. I feel like its my fault. He went to jail and hes a registered sex offender. Its been almost 2 years and i feel horrible. Not for but for me because i was so stupid. Has this happened to anyone else. How do u get over it?