"No matter how healthy a relationship is, there'll always come a time where you have resentful thoughts of your spouse. Those should be kept to yourself, as most of them pass quickly. The only time you should share them is if they're persisting in some behavior that is hurting you, and then it should be done calmly and not in the heat of the moment. For instance, if you got home from work tired to find your spouse binge-watching a TV show, but the sink is full of dirty dishes, the impulse may be to lace into them. Don't. Go ahead and do the dishes, and tomorrow, when that initial flash of anger has passed, discuss the issue.
People say arguments can be healthy in a relationship, but it all comes down to how you argue. Spouses, at least if they're good ones, know intimate details about you, your past, and how you think and feel. This gives them weapons to hurt you, and it may be tempting to use such weapons when angry. But if you know your spouse has a sore spot about their dad, and you say in anger 'this is why your dad never loved you', you have permanently damaged your relationship. And that damage builds up over time. Successful relationships survive because people rein themselves in at that moment. Even when they're angry, they don't want to inflict wounds like that. So whenever the impulse arises to use those weapons in anger, resist the temptation! You may forget what you did quickly, but they won't."
I couldn't agree more with this.