k-1/fiancees visa

I am a Canadian citizen, I will marry to a US citizen. I wonder if I need to apply Fiance/es visa (K-1) visa. I am in US now, I have a TN visa I am working in US now. I checked website, it says as a Canadian I do need K-1 Visa, however, my friend told me she had friend used B1/2 visa entered US and got mattied, they never applied K-1 visa. Anyone has any ideas? Thanks a lot.