I often let harsh words slip at my spouse when I am angry. How do I control it?

Words let slip in anger leave scars that take a long time to heal, so deal with the anger before it turns into words. The Prophet ﷺ said: “When one of you becomes angry while standing, let him sit down. If the anger leaves him, well and good; otherwise, let him lie down” (Sunan Abu Dawud 4782). Give yourself a pause of a few seconds before replying; the sharpest words often come in the first moment. If you feel close to exploding, excuse yourself briefly: ‘I need to calm down first, let's continue in a little while.’ Then come back and talk about the issue, without belittling the person. Apologise straight away if you have already gone too far. See communication & emotions.