This quote was used in the 4th talk, given by Paul Blackham. The talk can be found here.
“Lust is not the result of an overactive sex drive; it is not a biological phenomenon or the by-product of our glands. If it were, then it could be satisfied with a sexual experience, like a glass of water quenches thirst or a good meal satisfies appetite. But the more we attempt to appease our lust, the more demanding it becomes. There is simply not enough erotica in the world to satisfy lust’s insatiable appetite. When we deny our lustful obsessions, we are not repressing a legitimate drive. We are putting to death an aberration. Lust is to the gift of sex what cancer is to a normal cell. Therefore, we deny it, not in order to become sexless saints, but in order to be fully alive to God, which includes the full and uninhibited expression of our sexual being within the God-given context of marriage.”
[Richard Exley, 1989]