Remember what you admired and liked about your spouse when you first committed to a lifetime together. (And if you don’t remember, ask some of your friends from back them to remind you.)
When (if) you hit a rough patch, bring up that positive image of your spouse’s best self. And address that person. The way you were in the beginning.
It’s not easy, but so possible. And a much better way than falling into a downward spiral of fights or withdrawing from each other.
Depending on your own personality, you might attach this memory to a picture, song, scent, phrase, food. And conjure that up as needed.