Why others decide my happiness?

Though this is there for donkeys years but since last few months I have been realizing how my being happy or sad or whatever feelings I am going though is controlled and dependent on others. Citing some of the recent events - I felt depressed when Divyansh didn't come up with his expected results, when my friend Rajesh quit Rotary, excited with my new Mac, some great shots with the camera etc etc. We are taught to make our happiness dependent on others - some object, thing, people,events , conditions. Now I understand the lack of real long term happiness in my life is because of dependence on others. I feel I delay my happiness till things are just right. But life is never just right and future never comes - there is only now. Sunils untimely death should be an eye opener. Life around his family and friends just took a complete turnaround the moment the doctor said he had few months to live. Just 42 with two young daughters. It was a moment of shock more than I had ever experienced. But still why don't I learn? Why I keep on postponing my happiness? And the only reason I can find out is my dependency on others for my happiness. I have seen all my happiness being dependent on acquiring something or someone, seeing the result I desired, waiting for some pain to go away before being happy. Happiness has to be my decision and not a dependency. And to do that I have to change my state of being from dependency to freedom from dependency.