Hmmm. Since the cognitive behavioral therapy, I've come to realize that there aren't really any habits that aren't breakable. If you "can't" break it, it's like you've got a habit of saying you can't. I find it easier and easier to do things I should do and that I want to do, and not to do things I shouldn't. It's a discipline thing I never had before. Not that I can't go all self-indulgent every now and then, but overall, I feel like I have greatly improved my ability to say "No, I do NOT have to screw up [my diet, keeping the house clean, client business], it's NOT inevitable, just do the right thing!"
That said, put a bag of black licorice in front of me and my brain can come up with some pretty elaborate excuses! LOL.