Have you exposed this affair to anyone?

Stop arguing with him about it being an affair/not being an affair... He KNOWS it is... He's just playing games with your head... He thinks your pursuing him is flattering and sickly funny... In short you are stroking his ego and getting no closer to ending things that way

You don't TALK to end an affair, you ACT

You ACT with what you have, never mind evidence.. you have enough