AnnaBG, do you mean that the false facts might turn out to be true after some time, or am I misunderstanding you? Because even if he does get married, it might take him exactly the 5 years, if not more, to find a woman with exactly the same name, date of birth and other personal details as he specified in his TRV application) Not to mention the children that have to exist now.
Well, the 5 yr ban doesn't stop you from potentially applying after it is lifted, right?
If Canada really is your dream and you don't want to go to any other country, one option could be to come clean now, get the ban, and apply after it is lifted. And in the meantime try to build up a really good application, with travel history, funds etc. I just don't know how the ban will affect getting visas to other countries. Maybe start with some simpler destinations first. That will, of course, require a lot of time, work, and money. And I don't even want to think about the level of expectations that you'll achieve in these 5 years. I really hope it will be worth it if you do get there.
Whatever you decide - best of luck!