When the person who should show you more love than anyone is abusive, it's understandable that it would take a toll on how you feel about yourself as over time you may have started to believe what he is saying. Marriage isn't walking around on eggshells 24/7 so as not to upset your spouse. Are you getting anything from this relationship other than avoiding being alone? If he hasn't done anything to deal with his rage, it's only a matter of time until it surfaces again and I for one, would not stick around for that day.
About this other man. I'm sure it's much easier to think about leaving your marriage when you have a white knight waiting in the wings, but I would seriously consider trying to be on your own for a while and not jump into a serious relationship. I think it might help you to talk to a counselor and work through your insecurities so you begin any new relationship feeling strong about yourself. I know it's easier said than done, but take strength in knowing that the stronger you are as a person, the stronger your relationships with others will be. Good Luck
