It’s not healthy to keep ANGER inside for too long. If you’re too upset to speak calmly, you can write a note and put it where the other person will see it.
Here are 3 sentences that may help. First: “My dear, I am suffering, I am angry, and I want you to know it.” The second is: “I am doing my best.” This means you are practicing mindful breathing and walking, and you are refraining from doing or saying anything out of anger. The third is: “Please help me.”
Memorize those 3 sentences on top. Or write them on a small piece of paper, the size of a credit card, and put it in your wallet. Then when you’re angry, you can take it out, and will know exactly what to do. (Not my words.)