Why is He Torturing Me This Way?

Aunty Amara, Good morning ma. Please help me, 

I don't know what is happening to my relationship.

I have been with my boyfriend for three years now. It hasn't been easy for me but I managed to pull through. 

Even when he cheats and abuses me physically and emotionally, I still forgive him.

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.