The Love-Lust Dilemma
"Once a sexual interest becomes a potential or real mate, there is a strong tendency to begin to automatically transfer unresolved issues from your original family to the “new family figure.” When you do, your body begins a programmed response of inhibiting sexual energy toward that person.
This is the underlying factor that turns people off sexually to someone they love or care for. It is an involuntary reflexive shutting down of sexual feelings as the emotional attachment to that person grows."
-Dr. Stella Resnick from Heart of Desire