You did the right thing by breaking up with him. The work now is on staying apart. There is not much left in this relationship and as you state your age as 18 you have been with him for a large percentage of your life. I understand that’s a lot of time to have invested, but I wouldn’t keep hoping he will change. You don’t trust him, he will not apologize for his wrong doing, he bails on you, and much of the time you have been with him has been unsatisfactory.
The work is on grieving. Give yourself a chance to truly disconnect. I would start getting support from your friends to help you unhook and figure out how to move on.