Change Yourself
Everyone is flawed. Everyone. However, when someone else has to pay for your flaws, the situation gets a little troublesome. They either try to change you or go away from you ... both options not in your favor. To retain the love of your life, if you have to change for the better, why not? Again, don't do it blindly. However, if the expectation is reasonable, don't think twice. Show your ex you are capable of change.