Im losing the love of my life...HELP PLEASE!?

How can i prove to my boyfriend i can change and become a better person for him? he broke up with me about a month ago because he was so fed up with the problems we were having. mostly my problems, attitude, things i do, people i hang out with. Me and him have been together for 8 months but iv known him for about a year and 8 months or so. He lives in Florida and I live in Illinois, so you can imagine how hard it is on top of the problems we had to have a long distance relationship, especailly when your in love like we are with eachother. Im at the brink of completly losing him because of my jealousy, envy etc. I hate the fact that i can get like that, its like when i get mad or jealous or anything, i become this different person and i tend to say things to him i dont mean, sometimes very hurtful things. So my question again is how can i prove to him,what can i do, to get him back, to show him i can change, and become a better person for him? iv tried almost everything i could think of