Megan married Mark. She thought that this was the happy ending she was looking for - but since she kept on living, it was a beginning into a world she only partially understood. For instance, now Mark’s happiness is something she has to strive for as well as her own. Even worse, she finds that happiness as part of a couple isn’t just about them - everyone else seems to think that they get to influence her happiness, too.
In a life that continues past the wedding, it isn’t making the commitment that takes work - it’s figuring out how to keep the commitment.
Or maybe, figuring out just what that commitment really is.