Commitment issues in every day life

I feel (more like know) I have severe commitment issues throughout my everyday life. This has been effecting my life, relationships and health for a long time now, but feel like I should speak out so perhaps someone can relate and/or provide some advice on how I can work on it. I basically cannot commit to anything. I'm with a beautiful girl who I feel I love very much however not a day goes by were things don't frustrate me and I feel like I want to be left alone. I don't want to commit to having to share my life with someone else. But when I am single I get very lonely and feel like I need to be in a relationship again. All my life I have been told I'm very good at art. I like to believe I am also, however I cannot commit to long term projects. These issues have even kept me from making a living out of the thing I enjoy doing most. I've attempted to start businesses in tattooing and even graphic design, however gave up on them as I get frustrated and cannot commit to making myself work hard to make a successful career out of it. So I always revert back to boring desk jobs and feel like I'm wasting my time. It's something I know that if I work hard at, I can be very successful however I just stop when the going gets tough and just settle for my desk job, take the pay, go home and perhaps sketch 2-3 times a week. I've gained a lot of weight over the past 5 years. I hate how I look and feel. I've tried to change it but I give up. Try again. Give up again. In fact, junk food is the only thing I have ever committed to. I cannot even commit to stop smoking for the person I love the most. I stop for a week or two but then start again behind her back and keep it a secret. I'm 28 now and feel that these problems I have are starting to ruin my life. I am not sure if it is laziness or selfishness but I do know that I need to stop these things from taking over my life. If anyone can suggest something that might help, before I consult a therapist, it would be greatly appreciated.

You say "I am not sure if it is laziness or selfishness" You almost nailed it - it's not laziness or selfishness it BOTH.Seeing a therapist might be beneficial. Understand nothing change until you decide YOU WANT to change- which will require "action" on your part.