The Lovers: Catherine, Katherine, and Vincent
"Marriage, all in all, is a cowardly method that tries to subdue love through torture."
Growing up is hard enough without someone pushing you into it and although Vincent's day for manhood has long been overdue, Katherine's insistence that he start taking life seriously by pushing him towards marriage aren't helping. Whether she was a delusion or a demon, when the buxxom Catherine suddenly provides an out for Vincent, entangling him in an affair, it only further's his realization that he's just not ready and exacerbates his vilification of his long-time girlfriend.
Although it's easy to point blame at Vincent for his involvement with another woman while dating Katherine, the game does a fantastic job of making the player realize that staying with her may not be his best option. This story of infidelity, pressure, and the fear of breaking someone's heart handles it all with more grace than most films.