Here is one successful case:Should i invite him? I mean what would be the best reason of visiting? We want to get married wen he arrives canada and add up his name in my p r application.
https://www.canadavisa.com/canada-immigration-discussion-board/threads/visitor-visa-for-fiancée.543196/
More advice:
https://www.canadavisa.com/canada-immigration-discussion-board/threads/visitor-visa-for-fiance-to-visit-and-get-married.486599/
Spend a bit more time on this forum looking for similar threads. There are plenty. And then you can get to decide if he can go for it or not.