How to overcome bitterness from past relationship?

I know how you feel because the same thing happened to me. Being bitter gets a bitter outcome. You just have to realize that that was ONE girl who messed up. If you view every chick to be the same way, then you are putting your guards up too high. All these experiences are just to make us stronger and much more wise. I was bitter for a long time and saw that nobody was asking me out or anything. Then when I brought the guards down JUST A TAD...some really great guys came around. Like my mother always told me..."the next relationship that you get into, remember...fall in love, don't stumble".