You have two options be a bitter person or a better person!!
Sometimes what you think has ended just needs a few steps backward apoloize where it is due, show you care no matter what and wait. It is worth saving any relationship has made you grow as a person.
For whatever reason this can't happen then look at it from this point of view.. be grateful for what you had , dont entertain bitterness or anger for the more you hold on to these emotions the more deeper you get hurt and you turn out to be a bitter person.