Why is it so hard to stop thinking about him?

So we only were dating for 3 months (not even) and the first two months were good. The passion was great, he seemed to be way more into me than I was into him. He talked marriage, living together and a future. He wanted to meet my parents and family right away and said that he wanted to do that because he knew it would make me happy and I never even hinted to that fact. Later he was the one that wanted me to meet his parents and set a date for this to happen and when the time came he cancelled, said something came up. I was a little disappointed and pushed a bit because he had met my parents and it was only fair that I meet his. Anyway I ended up meeting his parents. He continued to get more engulfed in my family and life, however he would keep me away from his family get togethers and he never had a reason as to why. He always wanted to be on the phone all the time, and when I say all the time I mean from the moment we woke up and we would even fall asleep on the phone. I did not like being on the phone so much but whenever I would tell him that I would want to go he would ask why and was a bit clingy. Needless to say, the real problem started when seeing each other became less and less often. The whole month of April we have only seen each other once. His explanations were that he was busy and would see me when he had time. Keep in mind the phone contact was exactly the same (24/7). I however insisted that a relationship is not being on the phone all the time and not actually physically spending time together. He didn’t agree. His excuses were simply that “excuses”. He claimed that his life just became busy. Never really able to make time and it seemed as though he did not respect my time and thought that I was sitting around waiting for him for when he was ready to see me (and it actually was true, I was waiting around). So I decided I had enough and called it quits. I threatened a few times over the last month. He even made a comment “are you sure this time?” He did not want to end it but said it was my choice, and so I told him that he was giving me no other choice as he was not willing to meet me half way. I told him that I needed more from him, that I needed to know that he cared about me and spending time with me was important. He explained that being on the phone all the time should show me how much each cared. Needless to say, I told him that I could not do it anymore.
We told each other to take care and that was the last we spoke. We did not really argue, it was mostly me just showing him my frustration with the situation. The following day I had a weak moment and called him once (he did not answer) and then I sent him a text “Can we talk?” (no response). Later that day I posted a picture on Facebook of me spending the afternoon at the beach with a girlfriend and later that night he blocked me on Facebook. I have not had any further contact in a couple of days. I have every urge to call him but have not contacted him since that one weak moment a couple of days ago. I am trying to keep busy and move on with my life but I can’t help but constantly wonder why did he block me on Facebook and why has he not tried to contact me and will he ever contact me.