Story arc that would’ve been so cute if RIB+ gave a shit:
Kurt approves of teen marriage, but not Finn and Rachel getting married. So Rachel calls him a hypocrite, and Kurt explains that he doesn’t think she’s ready to get married to Finn but that he and Blaine could definitely get married at any time and they’d be fine. It depends on the couple. Rachel still isn’t swayed, so they challenge each other to a couples competition where they have to complete tasks with their sweeties like going grocery shopping together, living together for a couple days, taking care of one of those scary electronic babies from the child development classes, etc.
Kurt and Blaine win, but they had enough squabbles to realize they probably don’t want to get married until after college. Finn and Rachel call off their engagement indefinitely.