About 3 weeks ago, I was engaged/happy/ about to move in with my fiance.. and today I am single and indifferent. What a big change in 3 weeks! I had been dating this guy for 2 years, and we have been friends for 8 years. We always got along really well, but our relationship was extremely turbulent because of me

It ended with me leaving his personal belongings on his porch with a gorgeous engagement ring in an envelope. I did this because I was angry, irrational, and I was being spiteful.
No matter what he did, or what happened, or what solutions we had to ANY problem, I would cause another argument almost right away. Upon reflection, I think that I did this subconsciously because "it was never my fault" at the time. I would cause arguments over everything.. and I mean EVERYTHING. I always wanted to be alone, he didn't do anything quick enough, or what I wanted... and now I've been faced with thinking "wow I was a selfish brat" I care about him so much, but I kept treating him like I didn't. I did not want to be mean to him, I'd even say it in my head before I saw him "He's a good guy, I need to calm down, I need to be nice, we won't fight" - But it never worked. Ultimately, he could not handle me anymore - and in retrospect - I believe that he deserves better than what I had offered him.
I am not saying that I was always a horrible person, and that I was always mistreating him because we really did have our good days - days when we would be loving to each other. It makes me smile to think of those days, but it's hard to accept that I had actually made someone feel so awful. I always like to think - I want everyone to be happy, I want people to be able to come to me, and I don't ever want to hurt anyone. But - the truth is- I may think that way - but I have not been acting like that. I've been pretty distant to most people in my life.... and I am now acknowledging that there is a better way to live.
Now I am faced with the issues - was the problem that I was not truly in love with him? Do I have commitment issues? Why can't I control my emotions? Whether it be anger or sadness. Why would I treat ANYONE in the way that I treated him? Maybe I need to think about making some changes in my life.. for myself to become who I want to be. Maybe one day I will be able to be in a honestly rewarding relationship with someone who I can make feel lucky to have me because I am such a great person... Who really knows? I guess I will have to try.
I just though I'd vent... I've got a lot on my mind - and no one to really share my feelings with.