Most Helpful Guy
The key is accepting that hurtful fact and give it time, I know it sounds cheesy right now, i used to think the same when it happen to me, but try to remember the times you weren't with her, There was a time she wasn't in your life and still you kept on going. Don't feel bad about those happy memories, at least you had those moments and you should be happy about it, to your life people will come and go and that's good because you will have many experiences. Also don't say she deserves better, because no body is perfect probably she also hurt you many times, but is ok, is a relationship and there's not a single relationship out there that hasn't have there rough patches the key is to know how to overcome them. Just give it time, but try to accept it also distract yourself and do stuff you like, look for a friend or a family member you can spend some time.
Just in case when it happen to me i didn't like to hear this stuff because i felt it was none sense what people were telling me i felt like nobody understood the pain, but time pass and now i look back from time to time and i feel sad, but also i feel happy because i notice it wasn't that good of a relationship after all, If it ended it is not entirely your fault. Give time to yourself try to calm down and rationalize your situation with a clear head.