How you fight with your partner matters more than whether you fight. According to Dr. John Gottman's research, it's not conflict itself but how couples handle conflict that predicts long-term relationship success.
There's a crucial difference between 'I'm frustrated that the bills didn't get paid' and 'You're so irresponsible.' One addresses a situation; the other attacks character. The moment a fight becomes about who your partner is rather than what happened, it becomes damaging.
Gottman identifies contempt — eye-rolling, mockery, condescension, name-calling — as the single most destructive force in relationships. Even in anger, words like 'you're pathetic' or 'you're an idiot' leave marks that linger. These are lines that shouldn't be crossed.
Kitchen-sinking — bringing in every past grievance during a fight — is exhausting and prevents any single thing from being resolved. Agree to keep the conversation to the issue at hand. Other things can have their own conversations.
Ultimatums ('If you do that again, I'm leaving') are manipulative and erode trust. Don't make them casually in the heat of a fight. If you have a genuine ultimatum, it deserves its own conversation in a calm moment.
Even after a difficult fight, do something to signal that the relationship is okay — a hug, an acknowledgment, a shared moment. Don't let a fight just end coldly. Repair matters as much as the fight itself.