Saying sorry and meaning it is one of the hardest things to do. If not the hardest. It involves swallowing one's pride and admitting that they were wrong and the other party was right all along. By nature we don't like to admit anything that would expose our "soft bellies" (in the same way that it would mean the death of them, in the case of snails and hermit crabs, if it were so)
. In the same way that it would mean the death of our selves and egos if they were exposed for even a tiny bit. But even that kind of death doesn't even come as quickly as we want. Before that we will be subjected to much pain and torture that would be prolonged if we struggle and fight. I'm talking about emotional and mental pain, the kind that hits you in the gut. The kind where you can't identify who the enemy is. The kind that would eventually bring you down to your knees in surrender.
But there's a way out. Before it ever gets to that level, admit your wrong and turn away from ever doing that again. The pain of them consequences may come sooner or later but at least it would be more bearable because by then you already understand.