As someone who is also from the South (and proud of it!), I don’t personally use the word nor does my family, but it doesn’t bother me when others say it. Along the lines of what daybydaymama said, I think certain words that reflect the traditions or culture of a certain area are actually quite charming. Although our family doesn’t say ain’t, we do say y’all, fixin’ to, get around to it, as well as cutting the g sound off of ing words (goin’, makin’, havin, etc.). To us, it’s so second nature we don’t really think about it. I’m a pretty proper person, but in the South, I don’t think it means you’re an uneducated back woods hillbilly just because we don’t use “correct” terminology all the time. It’s part of our culture, just like the Brits have their own slang/cultural terms and New Englanders have theirs. If if bothers you, just tell him you’d appreciate it if he would use “I’m not” instead and then remind him every time he does use it. Growing up, we had a quarter jar. My dad was convicted of his foul mouth, so we got a jar for the center of our table which my dad would have to place a quarter in every time he cussed. It got pretty full, but he did clean up his language. 😉 Maybe this could work as a way to break this habit, if you’re really set on breaking it.
Take care now (said in my fairly thick Texas accent),
Lindsey