Caught Myself Lusting After a Student Again

I've been feeling guilty about it again. You know the old adage that 'they haven't aged a day,' but in my case, every day I see her reminds me of why she shouldn't have to age at all, if you catch my drift. I’m married with kids and a stable life, but there’s this pull towards one of my students. It's not about the physical form anymore; it's something more insidious, like wanting to challenge her or perhaps protect her from the world somehow. The thought terrifies me because I know it can't be real. But every time she smiles at me in class and nods enthusiastically after a lecture, I feel a shiver down my spine that has nothing to do with approval ratings or tenure. Am I losing my mind? Is this just an adolescent fantasy resurfacing, or is there something deeper here that needs addressing? What should someone in my shoes do?