This is my favorite antidote of Gottman's Four Horseman. You may here my reminder in session to "soften that start up for me" or "can you rephrase that using an I statement for your partner?".
What is an I statement?
You have something you want to bring up to your partner (or anyone really!) and you want to say it in a way that they won't feel criticized or get defensive. You'll have to phrase without using any blame or attacks.
A critical example would be
"Seriously? You never do the dishes when I ask you to."
A gentle start up would be
"I'm feeling overwhelmed by the pile of dishes, would you be able to get them done before I finish cooking?"
Can you hear the difference? Say it out loud to yourself and imagine your reaction. The second one feels a lot safer to respond to. There is no blame, criticism or judgement.
Here's the formula to a perfect I statement:
Start with "I feel _________" (This takes responsibility for your own feelings.)
Describe why without using "you" (To avoid them feeling blames and in turn getting defensive.)
Ask for a positive need "Can you do this?" instead of "Don't do that anymore".