It is really a personal choice, for me I like to keep them to show them that even tho they are not part of my life anymore, I am happy, satisfied and going forward with or without them, you might think that they do notice that but they do, people feel it when you detach and move on.

I forgot the most important thing, you need to forgive them for doing that, once you do you will feel much better and the emotional exhaustion that they put you through will go away for good.