You have a strong point about what's already in the mix of existing TRPGs. That said, I see a difference between rape and infidelity. Arthur discovering that Lancelot and Guinevere have an affair is one thing. Arthur discovering that Lancelot has taken Guinevere against her consent, by threat or force, is another thing entirely!Hell, the namesake family in Pendragon... Arthur is the product of rape by deception (via Merlin's illusion); Mordred is even creepier - his sire was raped by deception, too, and his mother was his father's half-sister. Lancelot is boning his best friend's wife for half the timeline.