One reason people go through the denial stage of a breakup is because they fear the negative emotions they will experience. Breaking up is hard to do and it leaves such a deep pain and feelings of emptiness and rejection.
Once you truly accept the breakup, you will be able to go through the healing stage. It isn't easy, but you will be able to move from the past and into a new stage of your life.
“Some people think it's holding on that makes one strong- sometimes it's letting go.”- Anonymous