Scratching an itch
"Scratching an itch" is a turn of phrase. A way to say that the person did so because "that is what they themselves wanted".
Have you ever sat with an itch, felt it, and then let it go away?
Itches are not about want. Itches are about an irrational urge to scratch and make it go away. Ignoring an itch is not a real possibility.
"Scratching an itch" is a consuming experience for some.