To my recollection, my parents had only two “big” fights in their almost-25 year marriage. The first was less than a year after they were married, when I was 6 years old. I was playing out in the front yard, when my mother stormed out of the house and said “GET IN THE CAR. We’re going to Grandma’s!”. I responded “Why can’t I stay here with Dad?” She shouted back “Because he’s not your father!!” (which is true, he’s my step father, but from the day they were married, I always called him Dad, and this is the first and only time she ever implied he was “less” than my father). We drove around for a couple hours, then back home, and I stayed outside and played some more while they made up.
The second time was about 2 or 3 years ago. My sister (who was about 15 or 16 at the time) called me tearfully saying that M&D had a big fight and Mom just drove away, and my sister was afraid she wasn’t coming back. It’s a testament to how infrequently our parents fought that my sister might have gotten scared Mom was leaving because of a single fight. It was such an unusual occurrence. (She came home a few hours later, btw).
Of course, they had the typical little spats that any two people will have when they spend so much time together. But those were the only two big ones.