I'm going to walk out of a restaurant on the guy I'm dating because he was in a bad mood.
Is there a reason for his bad mood?
The guy was being so rude to me because I made him realize he cheated on me when he was drunk
It is wrong to abandon people during a meal. It is wrong what he did but you should talk about it in private and not make a scene.
It's okay because I think his change of attitude is great.
While I don't think walking out on him is a good way to handle things. After having a talk with him about his cheating it would be understandable if you wanted to leave the relationship.