i think fights are worse when you are married. For one, both work on the assumption that the person is THERE, that your other half cannot go anywhere because now you are in the ultimate relationship of them all- the marriage. And hence you feel you can be daring about pushing the hurt limit…of what you can get away with. So words are harsher,less thought-out and geared towards more of an impact (since you are theoretically safe in your bubble).
What we can forget to take into account is the corrosion to the soul, the gradual eating away of trust and love, the battering to the heart and the eventual shutdown of all reaction that we are setting in motion. when fighting in a marriage, be very very careful.