In the jar of dreams I've put the main things I want to do before I die. There are things we can put in jars like wishes, dreams, notes of thankfulness, worries to pray about, memories we want to be reminded of.
My supervisor at one of my jobs said that her own family did a bowl or jar of the concerns the siblings had. At the end of a week or such they would pull out the pieces of paper one at a time reading their concerns, and the perspective gave them the sense that the things we worry about were temporary, passing by, and no longer relevant much of the time. Little things not worth arguing about or even thinking about, and yet we tend to take too much energy on them when they are "focused" on in our single span of attention.
In such cases, remind yourself in the heat of an argument of something big-scale concern more important, or of some value each other share, or of something you both are thankful for.
Donald R. Anderson. Aspiring writer. Amateur philosopher and amateur writer of Apologetics (i.e., the Catholic reasonings). Faith-driven kindred spirit.