My girlfriend broke up with me but we got in contact, need advice please?

What ever her reasons for the break up are, this was her choice and you need to respect that. I know it hurts and can understand and I commend you for allowing her to move on. You sound like a nice guy and it is her lost. Now, for her to get back in contact with an ex who cheated on her indicates she has some unresolved issues with him. Perhaps she needs some time to sort things out. In the mean time you do all you can to move on. I know it is not easy but if you take it one day at a time you will overcome this. My guess is that she is beginning to regret the break up, but don't allow yourself to sit at home depending on hope alone. Good luck to you!