30M- What is considered marriage in Canada?

Im early 30's and girlfriend is asking me about marriage. Long story short, I make it very clear that I have no intention of ever getting married on paper, and even cohabitation I'm very hesitant about. We are now together 5 years. She says that's fine with her, but since our relationship has been a secret from her family for the last 5 years and she's kind of tired of hiding it, that we can just tell them we are married (they live overseas) and then we can live together or just see each other more freely instead of hiding things. I don't believe she has any malicious intentions with this. For her family, boyfriend and girlfriend dynamic isn't really acceptable, it's kind of marriage or nothing. My concern however, are my assets and I know Canadian family law is a dicey game so I don't want to take any chances. I would appreciate any sound advice on how to best protect myself. If we were to 'fake marriage' to her family, we might just send them some photos and make it look like we are married. Thanks and Cheers.