Does getting married always revoke a Will?

As a general rule, getting married voids any Will that you currently have in place. This makes sense, given that once you get married, you have created a new legal responsibility for yourself to look after that spouse financially in your Will.

You can make a Will before getting married and prevent it from being revoked by including a clause in the Will that says it is made in contemplation of marriage to the person you intend to marry. You don't necessarily have to marry that person immediately afterwards, but if you marry anyone else instead, the Will is revoked. For example, if you make a Will in contemplation of marriage to John and then marry Bill, your Will is going to be revoked by the marriage.

Moving in with someone, even if you intend this arrangement to be a common-law marriage, does not revoke your Will. All jurisdictions include common-law spouses in the definition of spouse, but the right doesn't generally arise immediately. Usually there has to be some time spent living together, or a child of the union, before it's considered a common-law arrangement in law. In Alberta, the law of the unique Adult Interdependent Partner, a couple must live together for three years to be considered spouses. Even once a couple has reached that point, the Will is not revoked, but the spouse has the legal right to contest it.

People in common-law relationships are strongly urged to have Wills prepared, and to keep them up to date. Legally married couples should either make new Wills shortly after their wedding, or make Wills in contemplation of marriage before they tie the knot.