How can I stop being an asshole?

I can't lose and always have to be first and best. I'm unkind to people who are of no use to me, but deep down, I don't want to be like that, because I was never like that as a child. I was always a very nice child. I don't let others speak their minds and blame others for my mistakes. I don't "really" think much of myself. The person I've adopted to appear like I do is just a facade I created to make myself think I think highly of myself. I fell in love with a woman a few weeks ago, which has made me a little happier, and I'm hoping things will work out. I've reflected on my behavior over the past few months and decided to be a better person and stop being mean. I just want to be loved by her. How can I best achieve this? Do you have any tips?