Is it really OK to regret that it didn't work out and you left?
That you felt low because he used to put you on your place, belittle you, call you names, etc...
That he would only do his own way and won't even think about your situation (considering that you didn't mention some details)...
That he moves on very quickly and you realise that he never invested himself emotionally (well you kind of guessed beforehand that that was a case... )
After all what happened and that he treated you badly, is it really healthy to miss that person?