TL;DR: Man has latent mommy issues and now the both of them potentially suffers for it.
My shittake: Hold it in bruv. You dun messed up. Don't make it her problem. Sexual feelings gone? fine. Romantic feelings gone? I won't blame her if she leaves you, especially if you don't treat her well after losing feelings. Go through the motions and take care of her - you do right by her no matter what.
Edit: to round this answer out better I'm going to take a point made by the rest of the thread - get to therapy. There are definitely some landmine fine details that society glossed over and you might need some help after stepping on one.