visa exempt country-visa stamp? holiday visit...

[blueangel371115]

I am 'visiting' Canada long term starting tomorrow (as my summer job has ended) Though I am from a visa exempt country, can I request a stamp in my passport? As I will be filing for an extension later. They refer to something like that in the application ( I looked into it. I'm big on research ahead of time). I'm applying for common-law with my boyfriend and I want to solidify our case. Do I say as much at the border crossing? I'm already going to tell them I'm staying a month at least ( probably longer at this point, American Thanksgiving is in November and I at least have to return for that).
Which brings me to my next question, if I head home for the holiday, will it look like I'm just resetting the 'clock' on the six month period? That is not the case obviously. My boyfriend will also be traveling with me ( work permitting).