Complex sentence: Back at school, Will learns about Emma marrying Carl, and despite his shock, congratulates her as a sign of goodwill, while Finn breaks up with Rachel after she confesses that she made out with Finn to get back at him.
Split into simpler sentences: Back at school, Will learns about Emma marrying Carl, and despite his shock, congratulates her as a sign of goodwill. Also at the school, Finn breaks up with Rachel after she confesses that she made out with Finn to get back at him.