Conjugal is almost impossible to prove for a Canadian/US couple - it requires some sort of legal impediment that would prevent you from getting married and living together to qualify for common-law status. Thus, my concern in your situation is that they will drag this out (because they cannot refuse it without going through all the steps to ensure procedural fairness) but in the end determine you aren't qualified for conjugal status.
Is there a reason that your boyfriend cannot enter the US? Is there a reason that you cannot enter Canada? Absent that, the visa office will refuse because you can get married, and thus there's insufficient barriers to qualifying via a "normal" path. For example, if you did not wish to get married, you could go to Canada as a visitor and by extending your visitor status you could then qualify as a common-law couple. But even if you attempted that and were refused the visitor extension, they will still conclude you could get married - they don't have to grant conjugal just because you don't want to get married.
I would suggest you really look hard at your application and determine if an objective stranger will see sufficient impediments to you being together that you should be granted immigration status in this rather unusual class. If not, you might want to consider taking the steps necessary to qualify as either married or common-law, withdraw your original application and re-file it with the new relationship information.
Of course, if your relationship status changes between now and a refusal, you also have the option of appealing the refusal (to the IAD) and they will consider the new relationship evidence (even though CIC will normally not do that - they base it upon the status of your relationship at the time the application was logged into their system - the "lock-in" date.)
All the best to everyone!
