It seems you placed more importance on the relationship, than he did. Has he met someone else?
Unfortunately, you won't just get over him like that, it will take time. Try to busy yourself and find new interests, go out with friends and visit family. It's important you are able to talk to people and not just sit in alone grieving for your lost relationship.
If you are able to move, the do that, if not, then make little changes around the home, that won't be so familiar as to when he was there with you.
Good luck