nail biting

Soo I have a nail biting problem. I feel like mine is different than most who have the same bad habit. I do it because I actually like how it looks....oddly enough. And I don't get why..because to others it looks the same time I'm also odd because I want nice nails too. I was able to grow them out pretty long by getting shellac manicures..but I found that made my nails yellow/weaker whenever I didn't have it then I started to bite again. How can I stop this habit without resorting to shellac?! Can anyone show me their before/afters if you used to be a nail biter and successfully stopped? The pictures below are when I was actually able to grow mine out (with shellac) :(
Ps - unfortunately I am allergic to acrylic "fake nails" so I can't use those to help myself either.