My boyfriend gets angry over small things,and calls me names,has hit me like insane a lot of times,help?

he acuses me, talks rubbish when angry,has lied to me so many times,has disrespected me so many times in front of his family. i went back to meet my parents for a visit, when i came back i saw he called his ex girlfriend a couple of times. we have been in a relationship for approx three years now. i do see a good future with him, but one side of me is very very scared.
when he is not with me i miss her terribly,and want to be with him,i let go of his mistakes thinking one day he will love me softly and not be harsh,i think i cannot have emotions with another person in my life anymore.