Obsessed by the ex

Dear Therapists,
I do hope you will answer my question because I'm in a terrible need of advice.My ex-boyfriend and I had been together for 4 years and we really loved each other though sometimes I felt my love for him was stronger and more devoted than his.Of course, there were those little features in his character and behavior which annoyed me a lot, but I tried not to pay attention and restrained from any reproofs or remarks. For instance he smoked marihuana and used to give me the cold shoulder when he gathered together with his friends.There were days, however, he used to be extremely tender and was extremely creative in expressing his love.
My family didn't approve my choice very much.In my intention to have no secrets from them I had told them about my boyfriend's addiction to marihuana.
When my mother died unexpectedly when I was 22, he was by my side and I could feel his support every time.He helped me in overcoming the loss being patient enough to be a shoulder to cry on.
I wanted to returned him the favour when his cousin and his best friend died burning alive in their car in a car crash a year later.But he rejected my attempts to comfort him without even wanting to see me.
Short after the car accident he gradually disappeared from my life and his phone calls ceased.I decided not to call him either.Three months passed and my birthday came.Three months up to that moment I had been in an agony. Every night I had prayed not to receive a call from him if I was not the best thing he deserves and if there was a girl in the world more appropriate to him and more able to make him happy. But me on my birthday he phoned and wanted to see me. I refused. On the next day we had a night out and spent a really great time together without mentioning his long period of absence neither its causes. A whole week passed during which we went out, went to his place, had fun and sex as well.
One night while we were out he had a phone call.I told him to answer the phone though he was about not to do so. Telling me it was one of his friends, he left the car and went far from it.He had done that several times but for the first time then I sensed something.Though I knew it wasn't right, I lowered the music, so that I could hear him talking. I couldn't hear much but one word I heard clearly made me suspitious. At once I realized he was talking to another girl. All of a sudden I felt as if my heart has gone into my stomach – betrayed and abandoned. I can’t find words to describe that state. When he got back into the car I asked him if there was another girl.At first he denied but then told me the truth.What I learnt wasn't very complementary…Basically I was informed that he had met that girl in the shop where he works.She had been a little "elevated" had started joking with him. They had started to see each other first as friends, then as lovers long before the time his best friend and cousin died.He admitted he didn't know whether he loved her or not, but he was pretty sure he loved me.He would choose her only because she was still "a new experience" for him and he wanted to see what was in store for their relationship.She was confident and changed her mood very often - once she was tender and in another moment - cold like ice. He was sure I was faithful to him and on his disposal twenty four hours while he couldn't feel the same way with her.She had all the abilities to keep him intense.He was annoyed that at times that girl prefered to be with her friends instead of him.And she took much care about appearance, while I wore glasses instead of contact lenses for example. I also learned that at that moment that girl worked temporarily in a resort 300 km away from my native town (I wondered if he would havecalled me at all if she hadn’t been there)
I couldn't listen to him any more and rushed out of the car with him after me.He left the car with its doors open, started running after me, trying to convince me that he would leave her if I wanted that.
In the end we decided to remain "just friends" though he wanted hugs and kisses from me and my feelings were far more than friendly.During the next year he called me very often even after my contestant - his current girlfriend - returned from the resort she used to work in.He wanted to see me, but I rejected him.Now he calls very rarely and he lives with that girl.
I have a boyfriend now but he is not the boy I have dreamt of.He is very irascible and twice has even struck and kicked me for no apparent reason.Besides, he is not as well educated as I am - education is not estimated in his family.His parents are jealous because he is constantly with me and they don't like me because I'm 6 years older than him.That is why ,I suppose, I just cant't stop suffering for my ex-boyfriend and I am so interested in the life he leads.I wish I weren't. …And I very often think of his present girlfriend - the one who destroyed our relationship in such a mean way. I am curious to know how she has made him change so much. He has now found a second job and offered her to live with him.
Life is unfair. All my life I was doing my best to be a kind to other people and help my friends and family. Why did I have to lose both people I loved best. If my mother was alive I would have been stronger. Now I just want not to think of them. But I see them in Facebook, in cafes and restaurants, everywhere. The other girl also watches me even more than I do.
Please, dear therapists, tell me what things to do in order to ignore them. And why do I feel this way? Is it normal?