She didn't do the right thing at all. They are at a party which looks like it's likely to even be a wedding if so he might even know the person he was dancing with. In either case people generally go to parties where they know other people. Given that assumption and the fact that at a lot of parties people are drinking he seemed to be having a good time and just enjoying himself. The abusive part is her treating him like her property and pulling him off the floor by his clothes. If she's that jealous of a man doing what anybody does at parties then she's the one in the wrong and they shouldn't go to parties anymore. You said how insulted she must have felt? Imagine how insulted he felt when she embarrased him in front of all those people. And sure just like you said we are both drawing conclusions here, but why don't you look at his side of the situation too instead of just defending her actions? Or is she just completely justified in every way to you?