Peace sometimes means letting the last word belong to someone else.

The last word feels like the win and is usually the cost. Staying in an argument until you have said the final thing keeps you in it long after you stopped caring about the subject, and the other person rarely leaves convinced anyway. Letting it go is not agreement, it is deciding the evening is worth more than the point. That trade gets easier to make once you have made it once.

The next time you have a reply ready and the exchange is already over, do not send it. Put the phone down for ten minutes. Notice that nothing bad happens, and that you got your evening back.