As a previous poster said. How he sees it is not relevant. He is not the person who gets to categorise the different degrees of abuse, and what is/is not serious.
spitting in your face is grossly disrespectful, as disrespectful as physical abuse even if the degree of physical harm is less.
he doesn’t get to decide whether you stay in the relationship after what he’s done. You get to decide that and you don’t need to give any reasons. You don’t have to justify anything if you leave. I would not stay with someone who did this