Need to learn new habits

I am working on keeping my voice free of exasperation. It happens with my husband a lot. Though I am in a much better place with him than I was almost two years ago, I forget. Better because I thought he was forgetting on purpose and I was resentful. I am hoping that speaking in a calm, clear way will help him understand. Bad habits are ingrained and it will take a while to replace those with good ones. This is true of my dad also. I forgot that he couldn't see the doctor's report and so I sounded impatient. I don't have this problem with my mother because I am used to her processing issues. I am protective of my friend because she is mentally challenged, mentally ill, and physically handicapped, so am extremely patient. I am not used to my husband's or my dad's new health issues. I want to be reaffirming, supportive and helpful. I find it helps to laugh and not take life too seriously.