You can see the information at
Alberta's Adult Interdependent Relationships Act and you (HTML) - Publications - Alberta Justice - Alberta Justice
There are a series of factors the courts look at, and if, when looking at all the factors, it "feels" like an interdependent relationship, then it probably is.
I understand where you're coming from. If you want all the rights and responsibilities of marriage, then get married. And if you don't, there should be some way of opting out of that! But I don't think there is.