I know a therapist that works with a demographic that very few people can muster even an ounce of empathy towards. These people struggle with deeply disturbing and intrusive thoughts, and I'm amazed how this therapist can help make their lives more livable and avoid acting on their impulses.

That said, if your therapist was "destroyed" by your unsolvable but grave questions - you should just move onto someone else. That isn't likely to be a common occurrence.