He Tortures Me With My Past Mistakes and Shortcomings.

Aunty good afternoon ma. Ma please help me on this. 
I ended my relationship with my first boyfriend because he nags a lot. Then, he came back begging for us to be back together again that he has changed for good. I accepted him back, he supports me in everything I do. 

I then told him what has happened to me since we broke up, I told him about my ex, the abortion stuff and what made I and my ex to break up. He then told me it's okay. 
But to my greatest surprise, he started using the things I told him against me anytime we have problems. I have told him to stop those things because it's hurting me but he does it every time and it's now part of him. 
Ma, please am confused, what will I do?

From his attitude, it's obvious that he's yet to accept you and your mistakes as a human and the worst partner to be with is one who tortures your heart with your mistakes and shortcomings as a human being. 
If he's not willing to accept you without criticising or condemning you, please consider moving on with your life.