A Nurse's Secret Desire

I'm a 30-year-old nurse in a committed relationship. Lately, I've found myself fantasizing about my younger patients, imagining scenarios that cross professional boundaries. It's not like I act on these thoughts, I don't even look at them the wrong way, but they keep me up at night. My partner is kind and understanding, but how do I explain this to her? Is it normal for someone in my position to struggle with such impulses? Can anyone relate or offer advice?