A bit of backstory. My boyfriend (25M) and I (22F) have been together for about 3 years, and the entire time have had a very healthy and happy relationship. I have never felt such genuine happiness in a relationship before, and I have also not been particularly attracted to anyone else.
However, a few months ago, a guy who I used to see at my gym all the time happened to get a job at the coffee shop that I work at (small world, I know), and we kind of immediately hit it off as colleagues because we had casually chatted in the gym before. But I realised really quickly that I started getting incredibly attracted to him. I recently had to tell him that it's best if we aren't friends, as we both have very strong attraction to each other, and I obviously don't want to ruin my nearly perfect relationship. But I just can't stop thinking about this man, and I almost regret telling him that we can't be friends; it's been nearly a month, and I still can't stop thinking about him. I don't think I've ever been more attracted to someone before (even my own partner, which makes me feel terrible!). I don't know what to do or how to handle these feelings.
TL;DR I love my boyfriend and my relationship, but I can't stop feeling unbearably attracted to someone else, and I don't know how to handle it.