In general, it's a silly game that you are forced to play when coming into Canada. CBSA and CIC have completely different sets of criteria when it comes to foreigners in Canada.
When crossing the border you only need to worry about CBSA. Their job is basically to make sure you are coming in as a visitor only, and will be staying only up to the 6 months that are usually allowed for a visitor. If you tell CBSA you intend to enter and then attempt to stay 1 full year to qualify for common-law, or that you intend to apply for PR inland and not ever leave... you could be asking for trouble. They may assume if you are denied an extension you will stay here illegally, and there is more a chance for you to work illegally also. So basically your "intent" upon entering Canada, should be to stay up to 6 months, and what luggage you bring and what documents you have on hand should support that. So just bring luggage suitable for a visitor, show you have funds that will support you for 6 months or have a letter explaining a partner will be supporting you, have a return ticket back to US dated less then 6 months away (if flying or taking commercial bus service), and any other things you can think of that show ties to the US. And NEVER use words like "moving to" or "living"... it's always "visiting" only.
Also be careful about what you are carrying in your luggage and what's on your phone. CBSA can go through all your stuff including your phone, and if you have phone messages or documents indicating you intend to stay in Canada forever, you could be in trouble.
The good thing about "intent" is that it can change at any time and that is why as long as you are allowed into Canada by CBSA, you can then apply for as many extensions as you want and don't have to return back to US. Once you are allowed in, you can basically do what you want and what you said to CBSA is then irrelevant.
With CIC, they couldn't care less about how long you intend to stay in Canada, or if you're visiting or living here. No matter how long you told CBSA you will stay, you can then apply for as many visitor status extensions as you want in order to get common-law status, or you can apply for PR and stay here forever basically. As long as you maintain your legal status, you will never have a problem.
But then each time you exit Canada and re-enter, you have to go though the whole thing again. At least though once you have the PR app in progress, it usually becomes a lot easier with CBSA to enter.
The two of us do intend to marry someday, but we want it to be on our own terms, when we are more financially stable and emotionally ready and can relax and enjoy without feeling like we had any ulterior motives behind it. Oh, and Amalthea, I hope you didn't take offense to that. I don't know your situation and I'm assuming you did what was right for you. I just know I'm glad that we are waiting until all the stress of the immigration issues is behind us.
