hi,
I am 21 year old guy from India.
I am facing many problems now.
Before starting my story let me give little background about Love relationship in India.
Unlike western country, in India, girls and boys don't date unless they fall in love.
And person usually and mostly have sexual relation with only one person in his/her whole life.

Now my story.
Two years ago I was single. I had many dreams about my career. I wanted to do a Computer project, it was my dream to do it.
I was also hungry for true love. I didn't do anything for getting girlfriend or finding my love of life.
But when i met a girl in my class. First it started with texting, formal texting to late night chatting.
I loved her company, i was afraid to propose her. But after few months she proposed me.
Then i found out that she also loves me truly.
She had a boyfriend before for 1 month. Actually she didn't love him. She said "Yes" to him because he was emotionally blackmailing her.
But my girlfriend found out true nature of her ex-bf that he doesn't love her.
Her ex-bf used to spread rumors like they had sex etc etc. But in fact she doesn't even let him touch her.

When her ex'bf got news that she is in love with me he started to disturbing our lives.
He used to text her and me. He used to tell people false stories. I was frustrated because of him. It was like mental torture for me. He was literally psychopath It lasts 8 to 9 months.

I think it changed me. I have anger problem but after that events my anger was increased. I was unable to control my anger. I used to abuse my girlfriend when we had fight. I blame her because of her past. I said many bad things to her.
With time it became worse. Whenever we had fight i used to say many bad things.
But she is nice girl after all these she gave me many chances.
Sometime it feels i should leave her alone. But the problem is that i can't live without her but also I knew she is having problem living with me.

The problem is that, i think I am becoming like her ex-bf.
Please tell me whats disorder I have and solution?
Please also tell me name of disorder when you are acting like your enemy while dealing with him?