It's wrong to wish someone's relationship fails.
Sean's best friend just got into a new relationship and Sean is feeling lonely.
Sean wants to make sure he remains close with his friend.
Sean shows support for his friend's relationship and has a conversation with him about making sure they still find time to do things together.
Sean never shows any enthusiasm for his friend's relationship hoping to will an end to it into existence, so he and his friend can spend more time together.
Sean's friend appreciates the concern and assures Sean they will still have good times together.
Sean's friend becomes bothered by Sean clearly not liking his partner and the strength of their friendship dwindles.