There is absolutely no reason why you would ever have to give up your US citizenship. Even if you would get to the point that you would want to get Canadian citizenship, you can be dual. You can marry your boyfriend and he can sponsor you to immigrate. If you choose to come and live in Canada while you apply for this, you can't work until the paperwork is through. If you stay in the US while you apply, you can live there and work and come visit your boyfriend when you want. If you don't want to marry him yet for some reason, you can try applying to immigrate on your own. Read the immigration website and see if you would qualify as a skilled. If you apply for Bunac, you can come to Canada and work for a year. Also make sure you are taking lots of pictures and saving emails and phonebills in case you ever have to prove to immigration that your marriage is real.
