You are simply wrong in your beliefs on this point...and I see other posters already have provided you with examples quite easily. I would add that the vast majority of criminal cases, including sexual assault, are never the subject of media or written judgments so the fact more examples are not being cited to you in no way changes the fact that it happens all the time.
Others have also correctly noted that a prior history of sexual assault would in almost every case be deemed irrelevant and highly prejudicial to a new accusation and would be kept from being known by the judge or jury deciding guilt or innocence. The main exception being if there is a specific and detailed pattern of committing the offence (modus operandi or "M.O." in tv / movie terms)
To try and still be constructive...
The word you are searching for is corroborate or corroboration. One place you can find it being used is in the current Criminal Code of Canada, section 274, under the heading "Corroboration not required":
So, basically, for sexual offences, corroboration is not needed and it is wrong for a judge to suggest to a jury that it is.
But wait, there's more...
In the context of whether a person could be convicted of a crime on the basis of even the inherently risky evidence of a jailhouse informant, (spoiler alert, they still can) the Supreme Court of Canada said this (back in 2009):
https://www.canlii.org/en/ca/scc/doc.../2009scc4.html
How has that been playing out as of late? (since 2014):
https://www.theglobeandmail.com/cana...t-cases-metoo/
I am not saying it tells us anything about what will happen with these pending Hockey Canada allegations, but it is an interesting article worth reading and one that I think further undermines your argument.