US CITIZEN WANTS TO ESTABLLISH COMMONLAW W BOYFRIEND FROM QUEBEC

[travlgrl]

Since i am a US citizen and my boyfriend Canadian how do I establish common law since I do not need a visitor visa to stay for 6months or less but obviously cannot work since I have no work visa? How can we prove we will live together for 6months then I come home for a few days and go back , is this the best way and as asked how would I have record of our spending a year living together ? What will we need for proof And is this (staying for 6 months and coming home for a couple days and going back) the way to do it or should I apply for visitor visa anyway