First of all, I'm really sorry. That's terrible.
That said, don't worry about when he's going to come back. He might, he might not, but you know what? If he left you after ten years, why do you want to stick around?
Take some time, grieve, but focus on your life and putting that together. If he left you, he's not worth worrying over. That simple.
The guy I was committed to recently ended our relationship as well. I know it's hard (and it will be difficult for you even on your best days) but if he can simply abandon your union then he wasn't worthy of your affections. Anyone who can do that to someone is without the ability to love long term, as well as steadfastly. Please, don't lose yourself in your grief. Live on and live vibrantly. Time shall help mend your broken heart; after healing then I'm certain the right man will make himself known to you. Take care my friend. Don't lose faith.
So sorry that you are in this situation. The feelings of abandonment and betrayal are beyond understanding sometimes, and we get paralyzed, unable to move forward. You don't mention any reasons for him leaving, and not that it would "validate" someone walking out, but perhaps you would be open to connecting with a local resource for support groups or counseling to talk through this with someone who you can relay the details to, and they can comfort you and provide guidance for understanding and next steps.
Good luck...
The guy I was seeing got caught in a mess of lies & left me. He keeps trying to get me back & I know I’m better off without him. Yes…, I still love him but I love myself more. I wish you the best of luck.