Desensitize

Pornography can desensitize individuals to sexual content, leading to a need for more extreme material to achieve arousal.

Working in an Operating Room desensitized me to the sight of blood.

[…] child pornography is often used by pedophiles and child sexual abusers to stimulate and whet their own sexual appetites, and as a model for sexual acting out with children; such use of child pornography can desensitize the viewer to the pathology of sexual abuse or exploitation of children, so that it can become acceptable to and even preferred by the viewer;[…]