What you're experiencing is one of the disadvantages to having met someone from another country - it's not that easy just to move in together and figure out where the relationship is going. Although Canada and the US are close and share a border, they are two separate countries and each has its own immigration policy.
There is such a thing, in the States, as a "fiance visa" - which allows someone to bring their intended partner into the country to stay and to work . . . but then, after a period of time, you must marry or the sponsorship is withdrawn. If the relationship doesn't last, neither does the status. That's oversimplifying it, I'm sure - but the point is that Canada is not nearly so generous with their "temporary residence" policy. It is not possible to sponsor someone you think you might want to marry - you have to either get married, or you have to be common-law partners (having cohabitated for at least one continuous year) in order to be eligible to sponsor/apply for spousal permanent residence.
There are several ways to immigrate to Canada apart from spousal sponsorship, and there are ways to get temporary residence in Canada without it having to be about the relationship . . . someone could get a Study Permit, or if they find an employer willing to hire them who can get a positive Labour Market Opinion for the position (which involves proving that there are no qualified Canadian applicants), they can apply for a work permit. If the foreign national in your relationship can get into Canada through one of these methods, then that sets up the ability to "live" legally in Canada for long enough to be able to provide evidence of common-law qualification and then set the sponsorship process in motion after a year. It's also, sometimes, possible for a US citizen to come to Canada to visit for six months, and then get that status extended for another six months for a cumulative total of one year co-habitation . . . but it's not easy, there are no guarantees the visit would be extended, and there wouldn't be any ability to work or attend school. In addition, you live together for a year just to get to the point of qualifying to submit the PR application - after which you have another 6-12 months before permanent status is assigned . . . and the foreign national won't be working, basically, until that's done.
So, yes, they make it difficult - but it really isn't the government's responsibility to provide us all with a satisfying love life! And, while I get your point, this particular situation really has nothing to do with "fraud marriages". People in your situation actually want to be together (even if you haven't quite figured out whether it's for keeps), but find it difficult to do across immigration borders without benefit of marriage. People who enter into a fraudulent relationship (by immigration's definition) really don't want the relationship at all - they just want to get into Canada. So while it's true that Canada does their best to try to keep foreign nationals from entering the country and staying indefinitely, it's really not that unfair. The objective is to protect the integrity of the job market and healthcare for Canadians. There are an awful lot of illegal aliens in the States who are burdening the welfare system, taking jobs from Americans, and taxing the legal system. Canada, I think, is trying to do better for themselves. Where the US is finding it difficult to be tough on illegals, Canada is striving to prevent them from getting into the country in the first place.