How do you come to accept this?

It's horrible. But somehow you get through it. The best thing to do is focus on some positive changes you can make in your life to give you something else to feel happy and exicted about. If they dumped you, you need to feel good about yourself, so new clothes, new hair, drinks with friends, going dancing and getting some flattering attention from strangers all helps. Your message is a bit ambiguous though, so if they died or left for some other reason I'm not so sure. I still think it's important to focus on your self, but it will take a lot more grieving as well.