Think one of the most common realizations after a breakup is that you lost yourself somewhere in the relationship. You became so fully committed that you gave up parts of yourself to keep the relationship working. To make it worse is you realize the other person didn’t give up as much as you did because they never felt the same way about you. They never loved you enough to give up parts of themselves. Or they never loved you enough to accept you as you are without compromising who you are. When it’s over you are left on the cold hard ground.