Why am I not getting over this? Am I mental?

[Paradiso1]

A year ago I met a guy (by chance) and he pursued me fairly hard. We began dating. After a few dates (and no sex) I explained to him that I’m not looking for a Friends With Benefits and I only have sex within an exclusive relationship. He agreed to this. After 2 months of dating we had sex. 6 months later he told me: “You came along at a time when I was very vulnerable because I was feeling horny and you were just there. What do you expect me to do if I’m horny? Go to prostitutes? You were just there.”
He also added that he only likes me as a friend. When I got really upset and mentioned that a) I’d told him from the start that I don’t do casual sex and b) he’d spent months claiming he was my boyfriend and that we were exclusive, he just laughed and said “I’m a naughty boy! You’re a grown woman with her own apartment, you should have known the score.”
I’m actually really struggling to recover. My self-confidence is just shattered.

4 years and yes because of him. The dent in my self confidence affected pretty much all aspects of my life. You have had it far worse I fear. In my case it was 'only' emotional/mental abuse, where your ex seems to have gone straight to physical sexual abuse.
The freedom programme is excellent. The support and validation from others who have experienced similar is amazing.

Oh, and abuse thrives in secrecy. Far better to speak about it.
I was pleasantly surprised by some people who understood the dynamics of it but then sometimes shocked by the lack of understanding of others: which again brings me back to the importance of doing the freedom programme and counselling.