Quote: And I know that the nagging voice in the back of my head that says I'm being self-centered and sinning by thinking this way is just plain wrong.
I would suggest that you be careful not to get into a battle with that voice. Just regard it the way you would someone standing on a street corner selling tickets to the moon, or one of those infomercials that implies if you buy this gadget, you will grow hair, lose 50 lbs., and be a millionaire by the end of the week.
That voice and what it represents is misguided but not malicious. It's like a computer that was programmed incorrectly. Just turn your attention away from it. Dial down the volume. Don't feed energy into it by arguing with it, kwim?
The way you describe your grandfather is the way my bf's grandfather was (on his mother's side). He was an uneducated, circuit-riding preacher (I'm guessing he was born in the late 1880's, as my bf's mom is almost 90.) He used to punish the kids in ferociously cruel ways-- once when bf's mom and her sister were toddlers, they went outside of the front yard, which they were forbidden to do. He punished them by putting them up in the loft of the barn and leaving them in the dark overnight. During the night, he went outside and threw rocks at the barn to scare them. That was premeditated cruelty. I'm sure part of him thought he was doing it for their own good... but part of him just liked bullying weaker creatures. They were three and four years old, for God's sake!
You did what you needed to to survive, but now you've outgrown that way of being. Interesting that you're probably carrying your grandmother's anger as well as your wife's, in addition to your own.