In my early 20's someone in authority who I greatly admired, befriended me and then began to make some sexual passes at me. I resisted for 2-3 years as I simply desired a good friendship, but eventually caved in to him - for reasons that confuse me today - and had a number of sexual encounters.
Let me share my experience with you and see if anything jives for you. 20+ years ago an older man offered his "help" to me since I was a young man who was emotionally destitute and relationally challenged. My father was quite a distant man, so an older man reaching out to me to "help" me was an offer hard to turn down. I kept going to him with my issues anyway, so how could I say no?
He was a counselor at a local church and I knew him from my earlier teen years anyway. So I accepted his offer of help, and it started out good. Over time he became inappropriate in his touching me and his "counseling" methods. I was a kid with no idea of what therapy was, so I went along with it because I thought it was the right thing to do. It wasn't until a couple years ago that I accepted it was abuse. He took advantage of me and my lack of experience in the matter.
I guess my point with this example is that you aren't to blame for someone zeroing in on you like that. This guy I knew saw my needs and exploited them. He is to blame, not me. That guy in authority is to blame, not you.
I also had another kid in my childhood that I was in an abusive relationship with. Again I was emotionally starved and would take a raunchy relationship over no relationship, with a "peer."
Pleas go easy on yourself. It may take some time to sort out real intimacy from the false intimacy obtained in these past relationships. It can be done.