Playing devil's advocate... what if I (as a man) consent to sex because she says she's on the pill? And then she's not?

In Canada, having sex without a condom is "sexual assault", and is criminal. Lying about birth control isn't a crime because (paraphrasing the judgement) "No physical or economic harm has been done".

18 years of paying child support apparently isn't "economic harm".

The rape charge is on account of him fucking her while she was sleeping, the condom trickery was the basis for one of the other charges that has since been prescribed.

That may be true. In the real world though, there are no explicit legally binding statements uttered and confirmed before sex.