In some relationships, unhealthy ones to say the least, one person or the other uses their partner as a punching bag as a way of punishment; punishment for hurting them and making them unhappy. Instead of taking responsibility for their own happiness, they make you suffer. They may criticize you, belittle you, treat you with disrespect, give you the cold shoulder, and/or take advantage of you. This is mental abuse and it should not be tolerated. No matter what may have been said or done, no one deserves to be someone elses punching bag.
The person who is doing the punching obviously has some deep seeded need to hurt you as they think you have hurt them. This need comes from their inner suffering and has nothing to do with you or what you did. The action that caused their behavior only fueled the fire that was already burning inside of them. A healthy minded person would approach the problems in your relationship with love, compassion, understanding and forgiveness. The two of you would either find common ground that makes you both happy or you would decide to end the relationship amicably. You are not obligated in anyway to any person who chooses to treat you so abusively. It is not up to you to make them better, they have to do it themselves.
So this leaves us with the person who is being used as the punching bag. They allow it because they feel guilt. They think they deserve the punishment. They think they are no longer worthy of having a joyful life because of something they said or did. They believe it is their responsibility to make things right and to make their partner happy. But the truth is it is NOT up to you to make your partner happy. If you feel guilt, it is time to forgive yourself and let it go. Move on with YOUR life. Why would you want to be tied to someone who is mistreating you so badly? Why do you think so little of yourself to allow it? Why do you think your happiness is less important than theirs?
Staying in this type of relationship will never serve either one of you well. The only thing it will do is continue to make the both of you miserable and unhappy. Your life will no longer be YOUR life and the joy you once felt will completely fade away. It will be a long and treacherous road and in the end you will get to a point when you have to ask yourself why. Why are you allowing someone else to control you, your life and your happiness? By this time it may be too late to turn things around. Or maybe not. The choice is yours. So what is it going to be? Are you going to continue punching or are you going to continue being punched?