Having been cheated upon in both my long-term deals, I agree with everything that has been said above. The real damage from cheating is not the sex, it is the deception. The amount of lying required to attempt to successfully cheat on a partner is astronomical.

I have never felt the same nor full trusted my most recent partner, whom I "forgave" and did not leave. In retrospect, I should have left. She cheated because she likes the rush of the cheating and lying and the game. It is her nature. Is it your boyfriend's?