Fedora100 said:
If he stays with me in canada for six months, how long does he have to stay in the US before he can come over the border and stay with me again....for the next six months....just a couple of days??
How does immigration know how long you have stayed in canada?
How do they know you stayed one year?
As long as the line to get back into Canada is. He also doesn't have to go to the border - he can file extensions online or by mail. They will issue him a Visitor's Record instead of a new passport stamp.
The USA's passports now have microchips in them that are automatically recorded when scanned by the USA and Canadian's border agents. The USA and Canada share border data as well.
If he just decides to stay and not tell anyone - well there's not really an exit control. No red lights and sirens will go off at a CIC office at six months and one day. I know a man (from Germany) who has been in Canada illegally since August 2011.
The risk is being illegal. If he's caught, he can get banned from Canada. If he's deported, he would require authorization to return to Canada even after his ban. You getting married and sponsoring him wouldn't fix it either. You would still need to deal with the ban and apply for authorization to re-enter Canada. And yes, this
does happen to Americans.
My suggestion is he crosses the border as a visitor. He cannot "move" here and bring his household possessions. He will need to only carry a suitcase or two and a carry on bag or two - as if he was going for a long vacation. (He can bring some items of sentimental value, such as I brought a few collectables. My brother mailed me some other items that I couldn't bring on the plane/live without.) Enter with the intention of being a visitor and leaving if needed.
After a few months, he can decide how to extend his stay as a visitor.
Anytime he crosses the border, it's a best if you can be with him (although not always possible, of course).
After 12 months living together, then you can apply for his PR as common-law. As long as you do things right (provide ample proof, explain yourself logically to CIC) things should be fine. I've been a visitor since July 2011 with a PR application now in process. I've had 3 Visitor's Records and in each, I admitted to my intent to immigrate permanently with my spouse. That may be a bold move, but it has worked well for me. (I also made sure to include proof my husband could support me, so I wouldn't be needing to work illegally - so your boyfriend would want to show proof of his pension, etc.)