I have quite the delima.... Help?

Okay.... My ex Justin and I are really into each other but the reason for me and him breaking up we that he cheated on my by having w/ a nother girl... which i have forgiven him for, but he went out with a good friend of mine and almost got her pregnant. He says he is changed and I believe him, but my parents hate, i mean HATE him... BUT i realllly really want him back... what should i do?