In each of us there is a PARENT-ADULT-CHILD. When I talk to 51-yr-old Kelly using my Parent "should", she will respond as a Child. If I whine as a Child, she will respond as a Parent and she does both. My choice is to talk as much as I can as an Adult but consciously choose the skill when I feel tension in the conversation.
Last night, Kelly came and rightfully berated me for something I did wrong. I'm not good at quick answers, so I said nothing. If it's an important issue, we can bring it up again, maybe while we are having Sushi.
Talking as an adult is to use "I language" - not "You language" - and learn to express how I am deeply feeling.
In counseling, If using Adult language is difficult, I always suggest NO TALKING. To resolve an issue with our children, spouse or anyone, I suggest going to a public place to have a discussion. I've always done a lot of treating at favorite restaurants ONE-ON-ONE.