mate the answer your going to get is the same one most of us get in this situation "i just don't feel the same way about you any more"
it wont answer anything as there is no answer for why we just fall out of lvoe with people. one day youll be the one falling out of love and having Salomone ask you why your leaving them.. you wont be able to answer then just like you wont get an answer now.
So you gotta load of extra stuff to do now like cooking thats good, you gotta approach this in a "i can do better" find some recipes you like and start learning's o cook and cook better than she did
it will also help keep you active.
If you've ever had a deep cut and watched it heel it takes time same with your mind, but if your always looking at it you wont notice much difference bandage it up and look again in a week and you'll be amazed how much its changed.
Doing things is basically the way on sticking a bandage on the mental wound you've got.
keep focused on doing little things really well, like i said your morning routine each day try to make it better.
when you actually look back in a bit of time you'll be surprised how much better you feel about it, it still wont be fixed but focusing on it is the worst thing you can do.