Usually when arguing happens with the context of a romantic relationship or marriage it's usually about someone setting a "boundary" in an effort to demand some respect or an attempt to get their mate to "change".
Essentially arguments can be the potholes in the road of love.
When a couple first gets together they go through an "infatuation phase" where they make each other's happiness their top priority. The word "no" is seldom if ever used. Laughter comes easy, conversations lasts for hours, token gifts, flowers, candy, and weekend getaways done "just because".
However the "infatuation phase" only last for weeks or up to several months. Eventually someone "steps over the line" or unintentionally does/ says something which offends, disrespects, or is seen as inconsiderate, and possibly a betrayal of trust (in the eyes) of their mate. (Anger is the Mask that Hurt wears.)
Those arguments are a part of the discovery process of learning about one another, seeing your differences, and expectations.
In other instances it's a (battle of egos) and "power struggles" to determine who is going to be the dominant person in the relationship. Oftentimes a person may feel like they're always "the bigger person" or always "gives in" and occasionally they feel the need to (hold their ground on something).
Lastly there are some people who simply LOVE to argue!
I recall one woman writing an answer to a question stating she'd be completely bored with a guy who seemed to always (naturally) want what she wanted.
"I need to be with someone who will (challenge me) and make me grow."
Personally speaking I have all the "challenges" I need on the other side of my front door. Harmony and serenity at home is far from boring in my eyes. At home I want to lay the shield down and remove the armor.
Nevertheless some folks feel if there is no arguing/fighting from time to time the relationship becomes stale or passionless.
Some folks will start a fight with their mate as a form of "shock treatment" to put some new life into the relationship.
Naturally if you hate arguing and find yourself with someone who loves to argue it means you're with the wrong person.
Like attracts like and opposites attract divorce attorneys!
Compatibility trumps compromise! :)