Why is that when something is said in anger, the natural inclination is to say something back in anger? Then it escalates, and, more words are said in the heat of this anger. If this becomes a characteristic of your relationship, a downward spiral could occur and discord.
In Social Psychology, this process has been termed as Reciprocity, and there are 3 kinds:
Positive Reciprocity - saying a term of endearment to your partner/spouse and he/she says one back; a kiss is reciprocated with a kiss; a touch is reciprocated with another touch...positive. There is an expectation that a positive action will be met by a positive response.
General Reciprocity - gift giving, sending a greeting card and not expecting anything in return; giving your partner/spouse a massage with no expectation of reciprocation.
Sharing, equality, fairness, splitting responsibilities 50/50, mutual understanding and PROBLEM-SOLVING.
Sometimes 1 partner has more responsibility; however, as long as it all works out in the end, it will be OK.