Ah, well that's pretty much black & white then, huh...
Sh*t.
Frankly, I think you should just wash your hands of them both & the situation entirely, even if it's only temporarily. You need a chance to rest/recuperate. Let him realize what a nut she is, let her realize what a dick he is, they'll both be unhappy & you can have the last laugh. If someone comes to their senses after the fact & approaches you, the ball will be in your court & you can decide whether you are a merciful God or not.