How to get an Annulment?

I posted a previous question and got such negitive responses that I've realised .. I can never get a divorce !! .. I have to get an annulment. Here's the backstory .. When I was 18, I did a very stupid thing and got married, .. less than a month later me and the guy split and haven't talked since then. Now, 4 years later .. I want an annulment [the reason I waited is because honestly it's a lot of paperwork .. and I just was lazy, and also because I was young ... so I never even told my parents were getting married! .. So it took 2 years to even tell them]. ---- My grounds for an annulment are that -- my old boyfriend"husband" never told me he was a Canadian citizen, when we married I thought he was an American. That's grounds for divorce right? It was obvious after we married that his parents were behind the whole thing and that he married me to speed up getting citizenship. --- I don't want a future marriage tainted by this spot in my past -- because I would never tell my future husband I was married before, .. and covering that up until I'm dead just seems such a hle.