If he is just a dumbass, let the break up stand as it is now, finish healing, and then see if you want to give him another shot when you are coming from a position of strength and he will be glad.
I agree with dumping the dumbass.
I do not agree with giving him another shot in future. That might serve him well and make him glad, but it is not OP's job to make him glad. It is OP's job to create happiness for OP.
To help create happiness for self, OP could make it a personal policy to not date dumbasses again
once they reveal their dumbass-ness the first time. Why go back for more of "known dumbass person" rather than start fresh with a new person with better potential?