I'm 32 and I feel unsuccessful - with so many defeats in my life, how can I change?

I have found myself at 32 feeling like a loser. I have had a long list of defeats and failures in the last ten years, a list that might stun most people. I have had low self-esteem since childhood, but this current chain of shortcoming seems to have started when I dropped out of colllege twice in my early twenties. Around that time I fell in love with an international student from Africa - this became and eight year relationship and a courthouse marriage. Also around that time I started hanging out with the wrong crowd and began selling large amounts of pot. I got busted in 2004 and used my clean prior record to and a lot of money to a great lawyer to get my charge reduced. At that time it became my dream to be a Marine. I thought a Marine was everything I needed to be - strong, disciplined, honorable. In 2005 my wife who I loved so deeply left me for a 19 year old guy and broke my heart in half. I was shattered to the core. I followed up on my plans to be a Marine, but bailed out during the first week of bootcamp when I made a phone call to her and she told me I was the love of her life and that she wanted to be together again. Needless to say, that was an empty promise. I ruined my chance to be great because so much of my happiness depended on her. I feigned sucidal tendencies to get out - that feels very cowardly in hindsight. After that horrible failure, I decided I should do something in music, since that had been the one constant love of my life, so I incorporated my love for technology and got very interested in audio engineering. Went to an audio engineering school, came here to Nashville and have had little success in a year. I am working at a smoothie place making nothing. I look at my life and ask, what went wrong? Where did I screw up so bad? I feel that I have a good heart - I would never hurt anyone, steal, etc. I care about people. Why have I fallen so hard, and how can I get out of this chain of failure? I know this all sounds crazy but I have nobody to talk to, and I have to figure this out.