Tw Sexual Assault - am I wrong?

I was sexually assaulted by a doctor - gyno. This happened 3 years ago and I was a minor. I was very embarrassed and I didn't tell anyone, not even my boyfriend or my mom. I know this is a huge mistake. This still haunts me to this day. I eventually told my boyfriend but I didn't tell him the full story and details. I didn't want anyone to know what happened to me. Especially not my boyfriend because I thought he won't want me anymore and not even touch me because this creepy old guy did. He tried to kiss me and grab my ass and forcefully hugged me. When I was on the gyno chair he leaned close to me.. He touched my parts without gloves, with his bare hands.. I felt disgusting but I just stand there like a stone. I didn't do anything about it. I was just 16 and i was in shock. He was 70.

Today I told him the full story when he asked me because I couldn't keep it in myself anymore. And my boyfriend got mad because I lied to him. I told him I didn't lie, I just hide it and never told anyone. I know, looking back I should have reported it and told my mom, but I just want to keep this inside myself forever. I feel disgusting.

Is my boyfriend in the right to be mad about this? Was I obliged to tell him or not? I know I should have, but I think he should understand me. He told me it's the same as if he cheated on me and didn't tell me.

This thoughts still haunt me to this day. I don't know if I'll be ever be able to forget this.