I am so very sorry for your shock and devastation. The kind of vicious turning on us that addicts can do is brutal. It is a brutal experience for us.
The addict's heart can be very small and very cold. As I always remind others, the addict operates from the lizard brain, not the human heart.
Odds are high that he will want to come back to you. Prepare yourself for this. It is a classic pattern and codependents are so grateful to have the addict back that they jump right in, believe the remorse and regret, and forgive and reunite and then experience the fog of the addict honeymoon.
So please, when your body has released all its grief and agony, do your work: write down what he was like, why you couldn't take it anymore, and what it felt like to be pushed aside for drugs.
You will absolutely survive this and if you do your work, you will have a whole new rock-solid set of expectations for mutual loving relationship.
In the meetings I attend--Nar-Anon--we learn not to accept the blame the addict places on us and we learn to trust God's will and to RELEASE.
You are in hell now. You will ascend. Angels are all around you, dear.