Context is key here. Even in the most loving relationships people can have rows and say the odd unpleasant insult in frustration. Everyone I know has occasional arguments especially when there are stressful life events occurring.
It’s more the pattern of the whole relationship and how you are treated, whether it’s a general contempt and a feature of the relationship. Also in a healthy relationship arguments are resolved and people are able to discuss and compromise. One partner should not be walking on eggshells fearing speaking out of turn, or when they will face the next tirade for some minor fault.
So it’s bigger than the language of an insult, it’s the context of the whole relationship.