Have either of you thought of paying for a professional manicure? Or you could even get a set of nails sculpted on. For myself, I find that anytime I have a little money invested in something I will stop and think twice about damaging it. The sculptured nails probably could not be bitten through anyway and if you kept them on for a month or two you could surely break the habit in that time. It is just a habit, after all. I know any habit is hard to break but you'll get such compliments on your hands and nails that you won't want to chew on them. Good luck.