My Secret at Work - Vulnerable Truths and Desire

I’m in a long-term relationship with my partner of five years, but I have this thing that’s been gnawing at me lately. Every time my regular customer, let's call him Alex, comes into the cafe where I work as a barista, there’s an undeniable tension between us. He’s in his mid-thirties, and while he treats me like any other customer, every brush of our hands sends shivers down my spine. Lately, it’s gotten so intense that when we’re serving coffee or exchanging bills, I feel myself becoming wet with the need for him to touch me just a little more than necessary. Tonight, Alex was here and there was an air of intimacy around us that I couldn’t ignore. He leaned in close while placing his order, and as he whispered something about needing my help with a special drink, my mind flashed to what it would be like to lean into him, my breasts pressing against the counter as we kissed passionately, fingers already at work undoing each other’s clothes before they can touch coffee mugs or money. I know this is crazy. I’m not cheating on my partner, but these fantasies of Alex and me are consuming. Do others deal with this kind of intense attraction to someone who isn’t their partner? Is it wrong for me to be so fixated when we’re just a customer and barista relationship by day? I can’t shake the feeling that I’m living in two different realities right now, and one of them is flirting dangerously close to cheating territory. What should I do? How do you handle this kind of overwhelming sexual tension with someone who isn’t your partner?