What would you do in this situation?

I was just sitting in my dorm when all of a sudden I heard my neighbor (who is pregnant FYI) get into a heated argument with her fiancee. Basically, he was angry because he found out her and another guy expressed via text message that they wanted to fuck each other (it wasn’t planned to occur, it was just that they are both attracted to each other). Of course, it’s understandable that her fiancee is upset about this. She admitted she was wrong but kept defending herself by saying “nothing happened, it ended there, i forgot about it, I only want to be with you” etc. Her fiancee reacted by screaming at her to shut the fuck up, calling her a fucking whore, to shut her fucking mouth.. some banging around… why the fuck would you do that, etc. She was crying, he was livid.. I was even a little worried he was going to hit her, but I don’t think he did. They both ended up leaving.

If you were in this situation, would you intervene? or would you just let it play out (Keep in mind you have no relationship with this girl)... When she returned, would you go comfort her or just leave her alone?