john in Hull - Good suggestion. One way to defuse arguments is to simply let the other person have the last word, despite that almost irresistible temptation to nail them with a marvelously apt (from one's own point of view) comeback.
I have actually managed to do this the odd time. :-)
And hopefully I will manage to again!
When I do, I find it leaves me with a lot more time and mental energy for more harmonious activities anyway, so it's really worth it in the end.