Practicality and commitment

I would like to begin with this to get a brief idea about the problem, I was in a relationship with a girl for 3 years while we were still in individual different colleges , we lived in different cities after I got transfere to another college I wasn't able to study due to constant thought of her and family issues where I became rebelious since my parents forced me in that city to stay and study although everything was alright and they had no problems with me, apart from that I have put in my blood and sweat in this girl I left my education in order to be with her took a job in her city but finally she gave up on me and engaged another guy why did she do this so far I figure out it was because she wanted secured future but if so was the reason why did she commit and why couldn't she have patience why did she give up when I made my complete family agree for her all of them were ready to support her ? I'm a well deserved batchelor now I'm working in an international market with a hefty salary more then she could possibly imagine I still have this question in my mind why without any reason I was left in thin air

When you can, try to get some closure out of the situation. Call her to see if she can meet up with you one last time to talk about your feelings and for why things became the way they are today. It seems to me she didn't really know what she wanted while she was with you, and something about her was bad enough to drive her to separate from you and get engaged to another guy. Something's seriously up with her, and you need that closure before you can move on. However, maybe it is good that she did this since it kinda tells you the kind of person she is. You don't need to tolerate this at all, but I think having closure with her will be beneficial to you.