By her plan a fixed-term marriage would legally dissolve after four years, unless a couple visits a lawyer to renew it (a less expensive and onerous proposition than a divorce, she claims). A fixed contract might include a provision vowing not to blend finances and separate property fairly, and it would be something both parties can plan around, she said — no unexpected outbursts of ‘‘I want a divorce.’’ Think of it, Ms. Laliberté said, as a “legally governed trial period” that could lead to a lifelong contract.

If Canadian law actually changed to allow this, Ms. Laliberté, 27, and Mr. Bisson, 24, want to be the first wed this way — pioneers, if you will…

Her proposal, though, has pried open a conversation about the expectations of modern marriage and the state of commitment in a world in which hook-ups and “non-dates” have become the norm for many young people, and economically autonomous adults no longer “need” a life-partner. While proponents see the merits in being extremely sure before devoting for life, critics fear this kind of arrangement permits a kind of commitment-phobia they claim is eroding the institution and cheapening the promise to love and to cherish by nixing that bit about ‘‘as long as we both shall live.’’ Not to mention: what about kids?