What is the worst thing you have ever heard?

That is. In the midst of a late night philosophical discussion on the nature of love with a friend that bombshell was set off in a hypothetical situation and I was INCREDULOUS, slack of jaw and disbelieving what I had heard. How could you do that to someone? First of all just using someone for sex like that without emotional intimacy between partners is a bit stomach-turning, then to deceive a person over a period of time like that into being your partner when you really wanted someone else, and then the abuse done to yourself in forcing such a mental compromise is, to borrow a term from Ben Croshaw: SHAMPOO DRINKINGLY AWFUL.