My anger due to stress work and money broke up my relationship.. do you believer people can change?

The key to change in anyone is want, If you truly desire to change and its in your heart to change, then it is possible. Make goals for yourself. Start with a day by day goal, then weekly, then monthly etc. Sit down and figure out your triggers. Write them down and acknowledge them when you see them. Come up with ways that are productive in handling your anger for example if you feel rage coming on before it gets out of hand take a step back, take a deep breath and count slowly until you feel calm enough to handle the situation, or talk a walk. The key is to accept accountability and accept your faults, then acknowledging them and putting an effort to change. Also make sure that if she comes back, you don't get into a comfort zone and forget and go back to your ways. From here on out you must make a daily effort to changing the way you handle stress, anger, tension etc. Explain to her that you are learning and making an effort, yet you are not perfect. She has to be ready and willing to learn with you.