Annulments
It is not an easy thing to get a marriage annulled in Canada. In my over twenty years of practice I have only had a couple of cases.
In one file the soon to be husband was supposed to arrange for his divorce to be completed before he went to Las Vegas to marry his new spouse. He thought he completed this but he did not finish it all off (I was not doing the divorce). So he tried to get married when he was already married. You can not do that so the second marriage was annulled.
The other ground you see is that the marriage was not consummated. There is case law around this. Example: what was the reason for the non-consummation.
If you have questions give me a call or send me an email.