Short of very extreme examples (STDs, impersonation, Spycops) this is just lying. It’s still bad, but it’s nowhere near the same level of severity as rape.
Once again, you're trying to say that non-consensual must equal rape and that's just not the case.
Also consider the implications of re-criminalizing adultery. That doesn’t seem like a good route to pursue.
No one wants to re-criminalize adultery. Literally no one is bringing this up but you.
Literally this entire scenario we're describing. It's the same reason why signing a contract that had invisible ink makes the contract unenforceable. Let's turn this around, why is willing exposing your partner to STDs without their knowledge not a violation of consent?
Legality != morality. I can think something is morally atrocious while still thinking it should be legal, or at least not punishable.