The betrayal of family thing was something I had to go through about six years ago, but have since gotten over. Though I'll never really get over that huge feeling of disappointment weighing on my gut that someone I once respected so highly---my father---could be so desperately close-minded. The horrible person aspect? It's because my first inclination after many heated debates with most of the members of my family was to gloat. Six years of trying to show them that this was the right path, I feel like I deserve some "I told you so!" time, but doesn't change that it kinda turns me into an ass.
You must have gone through a difficult process of breaking away from the indoctrination. Losing family is hard, but good for you for freeing your mind to think for itself. I also have family members who belong to a fundamentalist religion, and while they secretly think that their invisible friends are better than everyone else's invisible friends, we are still able to be very close and loving and mutually accepting (I think, more or less, well most of us).
Sometimes the reason a person feels like an ass is because an ass would never feel like an ass. I wouldn't be too hard on myself if I were you. Sometimes when people become addicted to antiquated illogical dogma, you gotta use some tough love.