In an age when it's neither socially or legally necessary, why do Canadians choose to marry? This provocative documentary looks at a convention that is not only persistent but thriving. It begins with a young couple whose piercings and tattoos would lead you to believe they are not the marrying kind, but Kathleen McEvoy and Andrew Sherratt have decided to marry for reasons that are as old fashioned as the institution itself. It's the moral thing to do, they say. But there are couples who marry just to have the party. They are lured by the romance of the event and the idea of being prince and princess for day, encouraged by a huge wedding industry that promotes the sensational wedding. And if it’s not the couple who wants the marriage, it may very well be their parents who insist on the nuptials. Why Do We Marry? takes viewers beyond the ceremony to reveal the many reasons why people say "I do".