I think it's all a matter of perspective, for example as per OP, shitty people have and will continue to donate organs, doesn't preclude them from being shitty partners. Countless SOs and spouses have literally had their entire livelihoods funded by their partners, doesn't stop society from cheering them on when they illicitly find in a sneaky link something their partner was lacking and unwilling to work upon.
That all being said, my most brutal betrayal was to myself...1st in allowing my cheating ex- SOs excuses to cause me to try to "up" my game, so to speak, and 2nd, opting to cheat back(when I regained my senses and some self pride back) as opposed to just leaving cleanly and starting over with a clear conscience.